Self-Power Wireless Doorbell 1.32 Songs Home Welcome Door Chimes 2.150M Long Wireless Control Distance 3.Waterproof Door Bell 4.Four leverls of volume 5.Self-Power,No battery required Features 1 :Strong Signal It can penetrate 3-4 walls and wireless range up to 150 meters in open area,great for large house including willas, apartment,offices,shops,warehouses.etc. Features 2 :IP68 Waterproof level Rainy days can also be used,saed and durable Features 3 :38 Songs Home Welcome Door Chimes The doorbell can be muted when sleeping Features 4 :Not only a doorbell but also a pager When the elderly,babies,and pregnant women sleeping alone have needs,press the transmitter and the bell will ring. Features 5 :Smart learning mode User-friendly design Multi-type plug interface, EU UK US Plug ,there is always one suitable for you 1.Operating voltage:AC 100-230V 2.Power consumption:0.25w 3.Wireless frequency:433 MHz 4.Operating temperature:>-10~+45C 5.Ringtone volume:>50dB/1m 6.Transmitter:no need battery 7.Receiver size:L95xW54xH68mm 8.Transmitter size:L80xW50xH28mm 9.Wireless distance:150 meter(open space)