Features: 1.2 FOR 2: Plug in doorbell supports 2 for 2, can be used for double door double floor household, can set a separate corresponding bell. Simple and beautiful, wiring free, battery free, long distance. 2.SOUND PAGER: Self powered doorbell can also change the sound pager, sleeping alone baby and the elderly, pregnant women have needs, a press will know, guarding the family. 3.HIGH PENETRATION POWER: Wireless doorbell supports long distance signal transmission, wireless through the wall use, strong penetration, one to one signal pairing, do not worry about and next door string line. 4.LOUD AND CLEAR VOLUME: Self powered wireless doorbell volume is loud, to solve the trouble of the elderly can not hear, but also can be set to a key mute non disturbance, easy to use for the elderly. 5.IP68 WATERPROOF: Self generating doorbell is IP68 level waterproof and not afraid of the sun, which can extend the service life. The transmitter can be installed by paste or screw mounting. Specification: Item Type: Self Powered Doorbell_x000D_ Material: ABS_x000D_ Use: Can Be Used For Families, Villas, Hotels, Factories, The Elderly, Patients, Pregnant Women A Key Call_x000D_ Specifications: 2 For 2_x000D_ Doorbell Transmitter:_x000D_ Power Supply: Self Generated_x000D_ Doorbell Receiver:_x000D_ Power Supply: AC100V-230V_x000D_ Power Consumption: 0.25W_x000D_ Ringing: 38 Ringtones_x000D_ Transmission Distance: Open Space > 150m/492.1ft_x000D_ RF Frequency: 433MHz_x000D_ Ringing Volume: 50dB/1m PackageList: 2 x Doorbell 2 x Receiver 2 x Sticker 1 x Instruction Book Note: Please supply power according to the voltage used, using other voltage may cause fire and product damage.