The PROLINK PRO1501SFC Super Fast Charging UPS is designed to provide reliable backup power and voltage protection for computers, networking equipment, and office electronics. It helps maintain device operation during power interruptions and unstable electrical conditions. The UPS provides a 1500VA capacity and uses line interactive technology with Automatic Voltage Regulation (AVR). Additionally, AVR helps correct voltage fluctuations and provides stable power for connected equipment. The PROLINK PRO1501SFC features super-fast charging technology that reduces battery recharge time after power outages. Moreover, this allows the UPS to recover faster and become ready for future power interruptions. The UPS includes protection features against overload, short circuit, surge, and battery discharge. Furthermore, these safety functions help protect connected devices from common electrical issues. The PROLINK PRO1501SFC provides reliable backup support for homes, offices, and small work environments. Therefore, it is suitable for computers, routers, CCTV systems, and other essential electronic devices. The UPS features a practical design for easy installation and daily use. In addition, its line interactive operation provides efficient power management while maintaining equipment protection. The PROLINK PRO1501SFC Super Fast Charging UPS combines 1500VA backup capacity, AVR technology, fast charging, and protection features. As a result, it provides a dependable power solution for everyday electronic equipment. manufacturer link Specifications: Capacity: 1500VA / 900W Technology: Line Interactive UPS with AVR Charging: Super Fast Charging Technology Protection: Overload, Surge, Short Circuit, Battery Protection Application: Computer, Network, and Office Equipment Backup
Aokly Gel Battery 12V – 200A 58.5Kg manufacturer link
Legrand Ups Keor SPX Line Interactive 1KVA/600W- 310302 Specifications : Le grand ups keor spx 1kva 310302 UPS 1KVA 1000VA
Specifications : GENERAL UPS Type : Tower Phase : Single phase with ground Rating (VA) : 2000 Nominal Power (W) : 1600 Standard Model Dimension (mm) : 397x 145 x 220 (D x W x H) Weight (kg) : 17 Long-run Model Dimension (mm) : 397 x 145 x 220 (D x W x H) Weight (kg) : 6.8 INPUT Connection Type : IEC 320-C14 Nominal Voltage : 200/208/220/230/240 VAC Voltage Range : 110-300 VAC (Load at 50%) 160-280 VAC (Load at 100%) Frequency Range : 45 ~ 70 Hz Power Factor : >= 0.99 OUTPUT Connection Type : 3 x Universal socket (PRO902WS) 2 x Universal socket (PRO902WL) Nominal Voltage : 200/208/220/230/240 VAC Voltage Regulation : ±1% Frequency Range (Synchronized Range) : 47 ~ 53 Hz or 57 ~ 63 Hz Frequency Range (Batt. Mode) : 50 Hz ± 0.25 Hz or 60 Hz ± 0.3 Hz Current Crest Ratio : 3:1 Harmonic Distortion ; ≤3% THD (Linear load) ≤6% THD (Non-linear load) ALARM & INDICATORS Battery Mode : Sounding every 4 seconds Low Battery : Sounding every second Overload : Sounding twice every second Fault : Continuously sounding LCD : Load level, Battery Level, AC mode, Battery mode, Bypass mode and Fault CONNECTIVITY, CONTROL & MONITORING Front panel : Status LED, Function keys, LCD display Communication : Smart RS232* USB : Port BATTERY Standard Model Type : 12V / 9Ah Numbers : 4 Typical Recharge Time : 4 hours recover to 90% capacity Long-run Model Type : Depending on the capacity of external batteries Number : 4/6/8 Charging Current (max) : 1A / 2A / 4A / 6A Adjustable REAR PANEL 1. AC Input 2. Input circuit breaker 3. USB Communication port 4. RS-232 communication port 5. Intelligent slot 6. External battery connection (Only available for L model) 7. Output receptacles
The Twist Online High Frequency UPS 10KVA TWUP10000/HF delivers continuous backup power for servers, networking systems, and critical business equipment. It uses online double conversion technology for stable and clean power output. Additionally, the high-frequency design improves efficiency and minimizes transfer interruptions. Moreover, the UPS includes an LCD display for real-time monitoring and system alerts. It features internal 20x12V/9Ah batteries for backup operation during outages. Therefore, it helps protect sensitive equipment from voltage fluctuations and sudden power failures. Furthermore, the TWUP10000/HF supports pure sine wave output for stable operation with professional equipment. It also includes overload, short-circuit, and overheating protection for safer daily use. Additionally, the tower design fits server rooms, office environments, and IT installations easily. Specifications: 10KVA online double conversion UPS technology Internal 20x12V/9Ah rechargeable batteries LCD display for real-time monitoring Pure sine wave output for stable power delivery Overload and short-circuit protection system
The Beco GP1500 1500VA 900W UPS delivers strong and reliable power protection for home and office electronics. It keeps computers, routers, and monitors running during outages. This helps prevent data loss and sudden shutdowns. Peace of mind increases with reliable backup power. Moreover, the Beco GP1500 1500VA 900W UPS offers 1500 VA capacity and 900 W output for high-demand systems. It supports larger desktops and entertainment setups easily. Backup power stays strong during interruptions. This improves system stability every day. In addition, the UPS features built-in surge protection to guard appliances from spikes and unstable power. This adds important defense against electrical damage. Devices remain safe during storms and fluctuations. Safety stays consistent. Furthermore, the Beco GP1500 1500VA 900W UPS includes automatic voltage regulation to smooth dips and spikes. It balances voltage without manual adjustment. This helps extend device lifespan. Consistent power improves performance. Also, the UPS delivers dependable battery backup when electricity fails. You can save files and shut down properly before power runs out. This reduces the risk of data loss. Backup support feels reassuring. In addition, the Beco GP1500 1500VA 900W UPS has clear LED indicators for power and battery status. You can check conditions easily at a glance. This makes monitoring simple and fast. Moreover, the UPS includes multiple output sockets for connecting several devices at once. This increases flexibility for busy workstations and entertainment centers. You can protect all critical electronics with one unit. Furthermore, the Beco GP1500 1500VA 900W UPS supports quick plug-and-play setup with no complex steps. Installation feels easy for any user. Setup remains fast and hassle-free. Also, the compact and sturdy design fits neatly into workspaces or shelves. It blends well into home and office environments. Portability stays practical. Overall, the Beco GP1500 1500VA 900W UPS delivers strong battery backup, surge protection, and voltage regulation. It ensures steady power and protects electronics effectively. This UPS is ideal for users needing reliable, high-capacity power protection every day. Specifications: 1500VA, 900W, LED, Plastic Case Input: 140-290 VAC Output: 230VAC 50/60HZ 12V 9AH *2pcs, Universal Socket *4 + EU Plug With AVR, Bypass output Overload and short circuit protection
Specifications : High Reliability Advanced DSP (Digital signal processors) technology Variable speed fan Effective software and hardware protection function, robust self-diagnostic function, and abundant event log for check Advanced digital parallel technology High Availability Wide input voltage range, 50 / 60 Hz frequency auto sensing Linear derating in low voltage input reducing battery discharging times, extending the service life of battery Dual-input design, supporting independent bypass Output power factor improved from 0.9 to 1, load capacity increased by 13% Flexible battery configuration (settable 16 – 20 pcs batteries) Charging voltage and current configured by demands Ability to switch on the UPS with batteries Settable delayed start time when mains power is restored, reducing the impact on power grid or generator Two modes of frequency conversion: 50 Hz input / 60 Hz output or 60 Hz input / 50 Hz output High Usability LCD+LED display, multi-functional keys operation, friendly human-machine interface Powerful background software for parameters configuration and online updating Compact internal layout, miniaturized the complete unit for small footprint High Intelligence Advanced multi-platform communications: RS232, USB, RS485, SNMP and dry contacts communication interfaces Intelligent battery management, automatic floating / equalizing charge control, charger dormancy control, increasing battery life by 50% Energy Conservation and Environment Protection Active power factor correction (APFC), input power factor up to 0.99 High efficiency 95% (up to 98% in ECO mode) Automatic power On/Off according to the load capacity set by users Equipped with self-aging function
The PROLINK PRO700 Line Interactive UPS is designed to provide reliable backup power and protection for computers, networking devices, and other electronic equipment. It helps maintain stable operation during power interruptions and voltage fluctuations. With a 650VA capacity and 360W output power, this UPS provides practical power support for home and office environments. Additionally, its line-interactive design with AVR technology helps regulate voltage and improve power stability. The PRO700 supports a wide input voltage range from 140V to 300V AC. Moreover, it automatically senses 50Hz or 60Hz input frequency, allowing compatibility with different power environments. The UPS provides simulated sine wave output during battery mode and sine wave output during AC mode. Furthermore, the fast transfer time helps reduce interruptions when switching to battery operation. The built-in 12V 8.2Ah battery provides backup power for connected devices during outages. Therefore, users can safely save work and shut down equipment during unexpected power failures. The PROLINK PRO700 includes protection features against short circuits, overloads, discharge, and overcharge conditions. In addition, its intelligent battery management helps improve battery protection and lifespan. The compact design makes the UPS suitable for desktops, network equipment, and small office setups. Also, its low noise operation allows comfortable use in different working environments. The PROLINK PRO700 Line Interactive UPS combines voltage regulation, backup power, and essential protection features in a compact solution. As a result, it provides dependable power support for everyday electronic devices. Specifications: Capacity: 650VA / 360W Input Voltage Range: 140V–300V AC ±5% Battery: 12V / 8.2Ah sealed lead-acid battery Output Waveform: Simulated sine wave (Battery Mode) Protection: Short circuit, overload, discharge, and overcharge protection
UPS ONLINE 3KVA 2400W 1 YEAR WARRANTY ABSOLUTELY PURE SINUSWELLE – With this inverter / inverter you operate your 220V devices via a 24V battery and a continuous power of 2400W 3KVA. Inverter is a device that allows you to use electrical devices everywhere, even when you are not at the power source MULTIFUNCTION HYBRID UNIT – Thanks to the small LCD display, it is also possible to charge the batteries with AC / solar charge controllers, setting the input voltage range and charging current. MODERN PROTECTION FEATURES – The device has many modern safety features such as: overload protection, overheating protection, short-circuit protection, so it is also suitable for home appliances, as well as microwaves, air conditioners, refrigerator, fan and daylight lamp. HIGH QUALITY MATERIALS – Equipped with PWM control, the inverter generates a pleasing amount of waste heat.
The Twist Online High Frequency UPS 1KVA TWUP1000/HF delivers stable backup power for servers, networking devices, and office equipment. It uses online double conversion technology for continuous clean power output. Additionally, the high-frequency design improves efficiency and reduces switching interruptions. Moreover, the UPS includes an LCD display for real-time monitoring and system status updates. It also features built-in 2x12V/9Ah batteries for backup operation during outages. Therefore, it protects connected devices from voltage fluctuations, surges, and power loss. Furthermore, the TWUP1000/HF supports pure sine wave output for sensitive electronic equipment. It also includes overload, short-circuit, and overheating protection for safer operation. Additionally, the compact tower design fits home, office, and IT environments easily. Specifications: 1KVA online double conversion UPS technology Built-in 2x12V/9Ah rechargeable batteries LCD display for system monitoring Pure sine wave output for stable power Overload and short-circuit protection system
Description : The Professional Series (1P/1P) – Tower is an advanced, affordable on-line double-conversion technology single-phase UPS system. Tower versions are available with 1000VA to 10000VA models and these offer high reliability for workstations, server and network equipment. The Professional Series is designed with automatic voltage regulation (AVR) to protect against power outages, disturbances and spikes. High voltage battery chargers and battery extension assembly is available for the long run time application. Key Features and Benefits True Double-Conversion Online UPS Mircoprocessor control optimizes reliability Input power factor correction Output Power Factor 0.80. Wide input voltage (110V – 300V) Converter mode available ECO mode for enegry saving (Only available for 1 – 3 KVA) Generator compatible Adjustable battery number only available for 6K and up models Smart SNMP works well with either USB or RS-232 together Emergency power off function (EPO) only available for 6K / 10K models Optional isolation transformer available. 02 Years Warranty manufacturer link
Key Features Output Connections (1) IEC 60320 C19 Input Connections Schuko CEE 7 / EU1-16P Cord Length 8.2ft (2.5meters) Power Cord, C19 to CEE/7 Schuko, 2.5m Wide selection of Rack PDU power cords for a variety of IT equipment. Specifications : Output Overload Protection No Maximum Total Current Draw 16 Input Input frequency 50/60 Hz Acceptable Input Voltage 90 – 250VAC Number of Power Cords 1 Maximum Input Current 16A Maximum Line Current 16A Physical Net Weight 0.49lbs. (0.22KG) Shipping weight 0.66lbs. (0.3KG) Shipping Height 2.01inches (51MM, 5.1CM) Shipping Width 4.02inches (102MM, 10.2CM) Shipping Depth 7.99inches (203MM, 20.3CM) Color Black Environmental Operating Temperature 32 – 113 °F (0 – 45 °C) Operating Relative Humidity 0 – 95 % Operating Elevation 0 – 10000ft (0 – 3048meters) Storage Temperature -25 – 65 °C Storage Relative Humidity 0 – 95 % Storage Elevation 0 – 50000ft (0 – 15240meters) manufacturer link
The Prolink Online UPS 10KVA with LCD and Internal Battery is designed to provide stable power protection for servers, networking equipment, and critical electronic systems. It helps maintain continuous operation during power failures and protects devices from unstable power conditions. The UPS provides a 10KVA capacity and uses online double conversion technology. Additionally, it delivers clean and stable power output to support sensitive equipment that requires reliable energy performance. The Prolink Online UPS features an LCD display that allows users to monitor important system information. Moreover, the screen shows details such as input voltage, output voltage, battery status, load level, and operating conditions for easier management. The UPS includes an internal battery system that provides backup power during outages. Furthermore, it supports protection features against overload, short circuit, over-temperature, and battery problems to help protect connected devices. The Prolink Online UPS is suitable for offices, data centers, and professional environments that need continuous power support. Therefore, it provides a practical backup solution for important equipment that requires stable electricity. The UPS combines high capacity, online power protection, battery backup, and monitoring features in one system. As a result, it helps users maintain reliable power performance during unexpected interruptions. Specifications: Capacity: 10KVA UPS Type: Online Double Conversion Display: LCD Display Battery: Internal Battery System Protection: Overload, Short Circuit, Over Temperature Protection
Specifications : Brand HAWK Package Dimensions 59.2 x 54.5 x 19.8 cm; 9 Kilograms Item model number HAWK202011 Manufacturer HAWK Wattage 720 watts Are Batteries Included Yes Item Weight 9 kg
The Twist Online High Frequency UPS 2KVA TWUP2000/HF provides continuous backup power for servers, workstations, and networking equipment. It uses online double conversion technology for stable and clean power delivery. Additionally, the high-frequency design improves efficiency and reduces transfer interruptions. Moreover, the UPS includes an LCD display for real-time monitoring and system alerts. It also features internal 4x12V/9Ah batteries for backup operation during outages. Therefore, it protects connected devices from voltage fluctuations, overloads, and power failures. Furthermore, the TWUP2000/HF supports pure sine wave output for sensitive electronics and professional equipment. It also includes overload, short-circuit, and surge protection for safer operation. Additionally, the compact tower design fits office, server room, and IT environments easily. Specifications: 2KVA online double conversion UPS technology Internal 4x12V/9Ah rechargeable batteries LCD display for real-time monitoring Pure sine wave output for stable power delivery Overload and short-circuit protection system
APC 800VA BX800LI 415W UPS (IEC Plug) APC 650VA BX650LI UPS
APC Easy UPS On-Line SRV 10000VA 230V SRV10KI is a high-capacity online uninterruptible power supply designed for critical business infrastructure, servers, and data center environments. It provides continuous, clean, and stable power using true double-conversion technology. It delivers 10000VA / 10000W (approx.) power capacity for heavy-duty applications. Therefore, it can support multiple servers, networking equipment, and sensitive electronics during power failures or voltage fluctuations. In addition, it ensures uninterrupted operation for mission-critical systems. The UPS uses online double-conversion technology to fully isolate connected equipment from utility power disturbances. As a result, it provides consistent, regulated pure sine wave output at all times. It includes an LCD interface for real-time monitoring of system status, load, and battery conditions. Meanwhile, built-in protection features enhance system safety and operational reliability. APC designs the Easy UPS SRV series for enterprise-grade power protection. Therefore, this model is ideal for data centers, IT infrastructure, and critical business applications requiring maximum uptime. Manufacturer link Specifications: 10000VA high-capacity output Online double-conversion UPS system Pure sine wave power output LCD monitoring display Enterprise-grade power protection
Features and performances x Outstanding efficiency and overload. x Perfect management and limitation of AC sources. x Power shaving of the consumption peaks. x Automatic allocation of the power available. x Active filtering of the load steps on the genset. x Automatic protection of the sources against overload. x Powerful multi-stage PFC charger. x Ultra-short transfer time (from 0 to 15ms max.). x Automatic and efficient stand-by. x Compatible with AC coupling. x Display, programming and data logging. x RS-232 communication for remote supervision. x iPS Dim. : 44.50x20x17.2( LxWxH cm ) , 17.50 x 7.87×6.8 ( LxWxH inch) x Carton box Dim.: 53.5×30.5×30.5 (LxWxH cm) , 21.65×11.8×12 (LxWxH inch) x Weight : 25Kg ( 55lbs ) Model iPS 3700-24 Inverter Nominal battery voltage 24V Input voltage range 19 – 34V Continuous power @ 25°C 2000W Power 30 min. @ 25°C 2800W Power 25 sec. @ 25°C 5.6kVA Maximum load Up to short-circuit Maximum asymmetric load Up to Continuous power Load detection (stand-by) 2 to 25 W Maximum efficiency 86 – 90% Consumption OFF/Stand-by/ON 3W / 9W / 70W Output voltage Sine wave 220Vac (+/- 2%) / 190-245Vac Dynamic behavior 5 ms (on load change 0 to 100%) Overload and short-circuit Automatic disconnection up to 10 times restart attempt Overheat protection Warning before shut – with automatic restart Battery charger 6 step adjustable : I-U-Uo-Equalize-Uo(low)-U(periodic) Charging current adjustable 0 – 45A Maximum input voltage 265Vac Input AC voltage range Adjustable threshold from 150 to 265Vac Battery control Absorption end By duration 2 / 0.25 – 10 h or by current – / 4 – 30A Absorption voltage** 28.8 / 19 – 34V Periodic absorption voltage** 19 – 34V Floating voltage** 27.2 / 19 – 34V Reduced floating voltage 19 – 34V Equalization** By number of cycles (1 – 100) or at set interval (52 weeks) Equalization end By duration 4 / 0.25 – 10 h or by current – / 4 – 30A Deep-discharge protection 21.6 / 19 – 34V Reduced floating time 0 – 32 days Periodic absorption time 0 – 10 hours General data iPS 3700-24 Auxiliary Output 2 independent Transistor short circuit protected outputs Auxiliary Input 2 Opto Coupler Programmable Input 10V Æ 60VDC Net Weight 25Kg ( 55lbs ) Weight with the cartoon box 26.2Kg (57.5lbs) 1 Year warranty
Prolink PRO3000SFCU 3000VA is a line-interactive UPS designed to provide stable backup power for PCs, servers, networking devices, and sensitive electronics. It ensures continuous operation during power cuts and voltage fluctuations. In addition, Prolink PRO3000SFCU 3000VA supports a wide input voltage range of 140–300VAC. Therefore, it stabilizes unstable electricity using automatic voltage regulation (AVR). Moreover, it delivers a fast transfer time of around 2ms for seamless switching between mains and battery mode. Furthermore, Prolink PRO3000SFCU 3000VA includes four 12V/10Ah batteries for extended backup support. As a result, it provides reliable runtime for critical systems depending on load. It also supports simulated sine wave output for compatible devices. In addition, Prolink PRO3000SFCU 3000VA features intelligent microprocessor control. Therefore, it improves efficiency, protection, and battery management. Moreover, it includes indicators and alarms for battery, overload, and fault conditions. Overall, Prolink PRO3000SFCU 3000VA delivers strong backup performance, stable voltage regulation, and reliable protection for home and office power needs. Specifications: 3000VA capacity for PCs and office equipment Line-interactive UPS with AVR voltage regulation Wide input range 140–300VAC for unstable power Fast ~2ms transfer time for uninterrupted switching Four 12V/10Ah batteries for extended backup support
PCE UPS 2400VA Raad 1200W is a line-interactive UPS designed to protect computers, routers, and office equipment from power failures and unstable voltage. It provides stable backup power during outages and supports everyday device protection. In addition, it supports Automatic Voltage Regulation (AVR). Therefore, it stabilizes fluctuating input voltage without switching to battery mode. Moreover, it helps extend battery lifespan by reducing unnecessary discharge during minor voltage changes. It also delivers 1200W output capacity for connected loads. Furthermore, it uses simulated sine wave output. As a result, it ensures compatible backup performance for standard PCs and networking devices. It also supports external battery configurations, allowing extended backup time depending on setup. In addition, it includes built-in protection features. Therefore, it helps protect against overload, short circuit, and voltage irregularities. Moreover, it provides automatic switching between mains and battery mode for uninterrupted operation. Overall, PCE UPS 2400VA Raad 1200W delivers reliable backup power, stable voltage control, and essential protection for home and office environments. Specifications: 2400VA / 1200W capacity for PCs and office devices Line-interactive UPS with AVR voltage regulation Simulated sine wave output for stable operation External battery support for extended runtime Overload and voltage protection for connected devices
PCE EX Online 3 KVA 2700W is a double-conversion online UPS designed for continuous and stable power protection. It is used for sensitive equipment such as servers, network systems, and critical office devices that require uninterrupted electricity. In addition, PCE EX Online 3 KVA 2700W uses online double-conversion technology. Therefore, it provides zero transfer time between mains and battery mode. Moreover, it delivers clean and stable pure sine wave output for safe operation of connected devices. Furthermore, PCE EX Online 3 KVA 2700W supports a 3000VA / 2700W capacity rating. As a result, it can handle high-load systems such as multiple PCs and networking equipment. It also maintains consistent voltage regulation for sensitive electronics during unstable power conditions. In addition, PCE EX Online 3 KVA 2700W includes advanced protection features. Therefore, it guards against overload, short circuits, voltage fluctuations, and power failures. Moreover, it is designed for long-duration reliability in professional environments. Overall, PCE EX Online 3 KVA 2700W delivers strong performance, zero-interruption switching, and high-level protection for critical power backup needs. Specifications: 3000VA / 2700W high-capacity output Online double-conversion UPS technology Zero transfer time for uninterrupted power Pure sine wave output for sensitive devices Advanced protection against overload and faults
LiFePO4 BATTERY SYSTEM LPBF Series 48250-48300 48V 250ah Solar Panel Rechargeable Lithium Battery For Energy Storage System model LPBF48250 capacity 48V 12.5KWH Voltage 48V Rated Voltage 51.2V Charge Voltage 57.6V Discharge Voltage Range 48-57.6V MAX.Charge&Discharge Current 120A DOD 95% Modeles Connection 1-6 in parallel Ingress protection IP21 Cycle Life >6000, @25°C Working Temperature Range -10-50°C Net Weight(kg) 159KG Gross Weight(kg) 183KG Dimension(MM) 615*350*955MM 5 Years Warranty Specifications: LiFePO4 BATTERY SYSTEM LPBF Series 48250-48300 model LPBF48250 capacity 48V 12.5KWH Voltage 48V Rated Voltage 51.2V Charge Voltage 57.6V Discharge Voltage Range 48-57.6V 5 Years Warranty
Onduleur tour Keor LP avec batterie avec 2 prises de courant 2P+T + 6 prises IEC 10A – 3000VA 2700W – port USB et RS232 1 YEAR WARRANTY
INVO online INH1000 NVO Online UPS High Frequency 10000 VA, LCD Display Inbuilt Battery 16 x 12V/9 Ah Specifications: Specifications : AC Input Bypass AC Output Battery Fault Screen LCD AC Input Bypass AC Output Battery Fault Screen LCD 1 year warranty Manufacturer Link
The Twist Line Interactive UPS 1500VA TWUP1500/LI provides backup power protection for computers, networking devices, and office equipment. It uses line interactive technology with automatic voltage regulation for stable output performance. Additionally, the built-in dual 12V/7Ah batteries support continued operation during power interruptions. Moreover, the UPS includes LED status indicators for clear power monitoring and system alerts. It also supports overload and short-circuit protection for safer daily operation. Therefore, it helps protect connected devices from voltage fluctuations and sudden outages. Furthermore, the compact tower design fits home and office environments easily. The system also supports cold start functionality and simulated sine wave output for common electronic devices. Additionally, the automatic battery charging system improves operational reliability. Specifications: 1500VA line interactive UPS technology Built-in 2x12V/7Ah rechargeable batteries LED indicators for power status monitoring Automatic voltage regulation for stable output Overload and short-circuit protection system
