●Wide Usage: Input 120V AC,60Hz, Output 16V AC,10VA for residential, commercialand industrial low voltage power supply. ●Strong power: Resolve energy issues caused by Low-power supply, perfect replacement of your old 10Va doorbell transformers for better performance. ●Fuse protected: built-in fuse, fuse open when overload to prevent fire hazard. ●Eco-friendly: Eco-friendlyzinc plating technology , no pollution. ●Convenience of Installation: Free quick connector included. Turn OFF Power before installation. Open up the connector to 90°angle, insert 120V power cord and transformer’s input cord at both ends, clamp the transformer, screw down the output part to doorbell cord.