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 notice Operating 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 screws Easy 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 anything Button is waterproof, don't worry about extended use Specifications: Model: FA12 (Type 86 Big Button) Music: 60 music options Volume: 5 levels (can be adjusted to only flash) Transmitter: No battery required, press to generate electricity Receiver: Lights up only when the bell rings Transmitter size: 86 * 86 * 22mm Receiver voltage: Plug in the power supply for use (AC110V/220V) Receiver size: 70mm * 70mm * 22mm Remote control distance: 150M straight line on the ground (data from the factory laboratory)