Features: Premium flame retardant ABS material, secure and reliable. Battery free, mechanical energy self-powered, green and environmentally friendly. 110-260V wide voltage, sensitive and user-friendly, no wrong ringing. Stable signal and super penetrability, the farthest unobstructed working range up to 150M. 51 chord ringtones, 4 levels volume adjustment, decibels up to 95dB. IP44 waterproof rating, windproof and rainproof. Long service life, button life up to 200,000 times. Suitable for apartments, high-rise residential buildings, hotels, factories, hospitals, and etc. Specification: Condition: 100% Brand New Optional Type: White US Plug, White EU Plug, Black US Plug, Black EU Plug Material: ABS Color: Black, White Frequency: 315Mhz±0.5Mhz Host Working Voltage: AC 110V-260V Power consumption: <0.01W Working Range(open): 120-150m Waterproof: IP44 Chime: 51 Ringtones Volume: 4 levels adjustable(including mute) Package Weight: Approx. 190g/6.7oz Package List: 1 * Receiver 1 * Transmitter 1 * Screw Accessory 1 * Glue 1 * User Manual 1、Premium flame retardant ABS material, secure and reliable. 2、Battery free, mechanical energy self-powered, green and environmentally friendly. 3、110-260V wide voltage, sensitive and user-friendly, no wrong ringing. 4、Stable signal and super penetrability, the farthest unobstructed working range up to 150M. 5、51 chord ringtones, 4 levels volume adjustment, decibels up to 95dB.