Ultra-quiet standby power system seamlessly transfers home or business electrical needs to the battery bank/inverter system during power outages. Delivers an instantaneous 4-6ms transfer of of power to support critical appliances and most computers for up to 72 hours actual time dependent on wattage demand. Unit features longer lasting, maintenance free AGM Absorbed Glass Mat batteries. When utility power is restored and stable, the BPS3600AG automatically switches back to utility power and recharges the battery bank. Also acts as a surge protector between grid power and appliances. Integrated inverter/charger also does not allow backfeeding to the utility power grid. Standby system is also capable of collecting power from alternative sources solar arrays, wind turbines and power generators for recharging. Delivers 30 Amps of 120V power. 2-year limited warranty requires a licensed electrician for installation and wiring. U.S.A. Allows Backfeeding of Power No, Alternative Power Collection Yes, Batteries qty. 4, Battery Type Absorbed glass mat, Dimensions L x W x H in. 41 1/2 x 36 x 15, Electrician Required Yes, Amps 30, Automatic Switch Back Yes, Rechargeable Battery Bank Yes, Run Time hrs. 72, Running Watts 3,600, Solar Power Compatible Yes, Hardwired Yes, Power Volts 120, Works With Gas Generator Yes, Standby Unit Yes, Surge Watts 7,500. 4 long-lasting maintenance free AGM batteries 30 Amps @ 120V Can safely power appliances and computers Ultra-quiet operation Can connect Sentinel to gas generator to recharge batteries during extended outages Can be installed anywhere in home Can also be used with solar power requires solar regulator and solar panel We recommend the use of a trained professional for electric connections. If used with a generator we recommend the installation of a transfer switch.