Thor TH400 400 Watt Power Inverter Full output power - 400 watt/800 watt peak modified sine wave power inverter. Low noise/self adjusting cooling fan. Ground fault sensing - designed to protect people against electric shock Overload protection - inverter will automatically shut down if load exceeds inverter rating Smart Surge Control (SSC) ensures smooth start-up of appliances Short circuit protection - automatically shuts down until short circuit is removed Thermal cutoff - automatically shuts down if internal temperature exceeds safe design parameters