Voltage Transformer Ussw 300 A1Voltage Transformer USSW 300 A1 For powering in the car via socket and USB port (230 V~ 5 V?) For smartphones, laptops and mains powered devices such as a cool box, audio system or charger up to 300 W Protection against reverse polarity, overload, overcharging, short circuit and deep discharge of the car battery Gentle soft start function Active cooling system with fan Suitable for cars with 12 V batteries Robust aluminum housing with on off switch,