Features: 1.Battery Free: Self generating doorbell, wiring free, battery free, long distance transmission, equipped with two doorbells and one receiver, can be used for front and rear doors. 2.Long Distance Transmission: Strong penetration, signal matching, no about crossing line. Whether you use it in a few rooms away, it is always easy to be notified when someone calls from the door. 3.Ringtones: There are 58 optional ringtones, and the built in speaker can emit rich, clear and stereo sound. There are 4 adjustable levels of volume, and the flashing indicator light is easy to notice. 4.IP44 Waterproof: Made of premium materials, prevents itself from being affected by higher temperatures and interference. Could withstands various severe weather conditions, suitable for indoor and outdoor use. 5.Multiple Use: It can not only be used as a doorbell, but also as a pager, suitable for babies, the elderly, pregnant women, sound and light reminders, convenient for the elderly and ear disease patients. Specification: IItem Type: Self Generating Doorbell_x000D_ Material: ABS_x000D_ Transmitter Power Supply: Self generating_x000D_ Transmitter Size: Approx. 63 x 63 x 20mm/2.48 x 2.48 x 0.79in_x000D_ _x000D_ Transmitter Working Temperature: -20C to +60C_x000D_ _x000D_ Transmitter Transmission Distance: Open places larger than apprrox. 150m/492ft_x000D_ _x000D_ Transmitter RF Frequency: 433MHz_x000D_ _x000D_ Receiver Power Supply: AC110-240V 50/60Hz_x000D_ _x000D_ Receiver Power Consumption: 0.25W_x000D_ _x000D_ Ringtones: 58_x000D_ Receiver Volume: 90dB_x000D_ _x000D_ Receiver Working Temperature: -10 to +45 PackageList: 2 x Push Button 1 x Receiver 2 x Sticker 1 x Manual