Feature: 1. Two for Two: Wireless doorbell adopts two for two design, which can be used for double door and double floor apartment. It can be set with a separate corresponding ringtone and 38 reminders. 2. Battery Free, Waterproof: Self generating wireless doorbell, wiring free, battery free, remote, convenient and practical. It is IP68 waterproof, which can prolong its service life. 3. Multipurpose: Door bell is not only a doorbell, but also a pager. It is suitable for babies, the elderly, pregnant women, etc. Who sleep alone. It can be known by pressing it. 4. Long Distance Signal Transmission: Wireless doorbell uses long distance signal transmission, wireless through wall, strong penetration, one to one signal pairing, so don't worry about stringing with the other door. 5. Adjustable Volume: Door bell has a large volume, which can solve the problem that the elderly can't hear. You can also set one button mute and do not disturb to facilitate the elderly to use the sound at will. Specification: Item Type: Wireless Doorbell Material: ABS Usage: It can be used in homes, villas, hotels, factories, old people, patients and pregnant women for one click calling. Specifications: Two for Two Doorbell Transmitter: Power Supply: Self Generating Doorbell Receiver Power Consumption: 0.25W Ringtones: 38 Ringtones Transmission Distance: Open Space＞150m/492.1ft Radio Frequency: 433MHz Ring Volume: ≥50dB 1m/3.3ft. Package List: 2 x Doorbell 2 x Receiver 2 x Sticker 1 x Manual Note: Please supply power according to the voltage used. Other voltages may cause fire and product damage.