Feature: 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 Material: ABS Use: Can Be Used For Families, Villas, Hotels, Factories, The Elderly, Patients, Pregnant Women A Key Call Specifications: 2 For 2 Doorbell Transmitter: Power Supply: Self Generated Doorbell Receiver: Power Supply: AC100V-230V Power Consumption: 0.25W Ringing: 38 Ringtones Transmission Distance: Open Space > 150m/492.1ft RF Frequency: 433MHz Ringing Volume: ≥50dB/1m. Package List: 2 x Doorbell2 x Receiver2 x Sticker1 x Instruction Book Note: Please supply power according to the voltage used, using other voltage may cause fire and product damage.