The wireless doorbell offers a wide selection of 60 melodies and 5 volume levels to meet your needs for different occasions. Flashing light with audio alert indicators which is easy for people including the hearing impaired to noticeOperating range up to 500ft / 150m in open area, ensures you to hear and answer the doorbell in time. You will never miss a visitor even if you are a few rooms away or on another floor. Easy to install with the double side adhesive tape or the screwsEasy to install. Just plug the receiver into power socket and attach the transmitter on door, you don`t even necessarily have to make holes or damage anythingButton is waterproof, don't worry about extended use Specifications: Model: FA12 (Type 86 Big Button)Music: 60 music optionsVolume: 5 levels (can be adjusted to only flash)Transmitter: No battery required, press to generate electricityReceiver: Lights up only when the bell ringsTransmitter size: 86 * 86 * 22mmReceiver voltage: Plug in the power supply for use (AC110V/220V)Receiver size: 70mm * 70mm * 22mmRemote control distance: 150M straight line on the ground (data from the factory laboratory) Package included: 1 x Transmitter 2 x Receivers 1 x English User Manual 1 x Pack of Installation Accessories