♬ 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 practical, more energy-saving and more practical than the old one. ♬ 45 Beautiful Chimes & Melodies: Offers 45 classic melodic chimes with adjustable volume control and diverse selection to meet your needs. 4 adjustable volume levels from 0dB to 90dB, which is loud enough for old people hear; enjoy pleasant melodies whenever someone rings your doorbell. The LED indicator gives you a visual form of notification (a great feature for the hearing impaired). ♬ Waterproof IP44: IP44 rating Waterproof design of the transmitter, made of ABS, non-toxic, safe and recyclable, can operate at temperatures between -20 ℃ and 65 ℃, and withstand various harsh weather conditions, sunshine, rain, snow, frost etc. Widely used for home, office, hotel, villa, hospital, office, apartment, school and other suitable fields. ♬ Long Wireless Range: With 150M/500FT wireless range, 2 plug-in receivers included, won't interfere with other equipment in your home or your neighbors; ensures that you will never miss a visitor, even if you are you a few rooms away or on another floor. Ideal for large homes, warehouses, offices, etc. ♬ Easy to Use: Convenient and easy to use design for better user experience. Simply stick the doorbell next to your door using the included double-sided tape or use the screw to mount the cover to the wall. then plug the receiver into a power outlet.