2PCS automatic wireless doorbell, 4-level volume, safe and durable, easy to install Features? 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 Strong Signal?150M Long Wireless Distance 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. Waterproof Door Bell?IP68 Waterproof level Rainy days can also be used,saed and durable 32 Songs Home Welcome Door Chimes The doorbell can be muted when sleeping 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. Smart learning mode User-friendly design Multi-type plug interface, EU UK US Plug ,there is always one suitable for you How to pair signals In fact, when we tested the product, it was already paired, and you can use it directly after you buy it back.