Features: 1.Thoughtful Design: This product has two doorbells that can be used for the front and rear doors, and can set a separate corresponding music ringtones, this is a wireless doorbell without wiring which is more beautiful and neat. 2.Long Range: This wireless doorbell has a strong penetrating power, the signal can penetrate 3?4 walls, in the open areas up to 150 meters. 3.Power System: This doorbell doesn't need any battery, you don't have to worry about when the battery will run out, it is a wireless that built in self generating door bell. 4.Multifunctional: The wireless doorbell has a clear sound quality and a total of 38 doorbell music can be switched at will, including classic doorbell sounds and other musical ringtones. 5.Reliable Material: This wireless doorbell is made of ABS material, which is hard and durable, waterproof and wear resistant. 6.Suitable Occasion: Great for large homes, apartments, offices, classroom, villas, hotels, warehouses, townhomes, small businesses. Specification: Item Type: Wireless Door Bell_x000D_ Material: ABS_x000D_ Usage: Can be used for families, villas, hotels, factories, the elderly, the sick, pregnant women one touch call_x000D_ Doorbell Parameters:_x000D_ _x000D_ Power Supply: Self Generating_x000D_ Transmission Distance: 150m without occlusion_x000D_ Rf Frequency: 433MHz_x000D_ _x000D_ Receiver Parameter:_x000D_ Ringtone: 38 (4 gears adjustable)_x000D_ Ring Tone Volume: 50dB/1m PackageList: 2 x_x000D_ _x000D_ DoorBells 2 x Receiver 2 xStickers 1x Specification Note: Please follow the use of voltage for power supply, the use of other voltage is easy to cause fire and product damage!