•Working together with the doorbell button. Just press the button and the doorbell will receive a signal, you immediately know that someone is coming •Operating range up to 100m in an open area when there are no obstructions •Higher penetration without worrying about signal obstruction ensures you will never miss a visitor, even if you are a few rooms away or on another floor •Easy to Install. Just plug the receiver into a socket, and mount the doorbell transmitter on the wall or anywhere you want, the effortless installation •Features 38 melodies and 4 level adjustable volume. It meets your different needs. Setting different ringtones for different receivers can let you know which door the visitor is at •Dustproof and waterproof, suitable for any home, townhouse, apartment, office, school, hospital, hotel, etc Specification: •Button: •Power supply: Self powered •Weight: 35g •Distance of transmission: 100m (no barrier) •Working frequency: 433MHz •Appearance size: 70mmx45mm •Working temperature: -20℃～+60℃ •Doorbell Receiver: •Power supply: AC 110V~230V, 50/60Hz •Music: 38 Melodies •Weight: 50-55g •Distance of transmission: 100m (no barrier) •Working frequency: 433MHz •Appearance size: 67mmx50mm •Working temperature: -10℃～+45℃ Package included: •1 x Doorbell •1 x Button •1 x English and Chinese User Manual •Other things not included