Feature: 1. No Battery Required: Self-generating wireless doorbell, no wiring, no battery, long-distance transmission, two doorbells and one receiver, can be used for front and back doors. 2. Long Working Range: Strong penetration, signal matching, no worry about cross-line. Whether you use it in a few rooms, it is still easy to be notified when someone calls from the door. 3. 58 Ringtones: There are 58 ringtones optional, and the built-in speaker can emit rich, clear, and stereo sound. There are 4 adjustable volume levels, and the flashing indicator light is also easy to notice. 4. IP44 Waterproof: Premium materials to avoid being affected by higher temperatures and interference. Can withstand various extreme weather conditions, suitable for indoor and outdoor use. 5. Used as a pager: 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.