No Battery Required: Our wireless doorbell transmitter uses unique PUSH-RF technology. When you press the button, the kinetic energy is converted into an electrical signal that rings your doorbell wirelessly. No more worrying batteries. More convenient, more energy efficient and more practical than the old one. Waterproof IP44 & Temperature Display: IP44 Rating Waterproof design of the transmitter, made of ABS, non-toxic, safe and recyclable, can work in temperatures between -20 ? and 65? , and withstand various harsh weather conditions. LED temperature display screen, Celsius/Fahrenheit temperature appears when the receiver does not ring, can be used as an indoor thermometer. 38 Beautiful Chimes and Melodies: Offers 38 classic melodic chimes with adjustable volume control and diverse selection to meet your needs. 4 volume levels adjustable from 0dB to 100dB, which is loud enough for the elderly to hear; enjoy pleasant melodies every time someone rings your doorbell. The LED indicator