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-saving and more practical than the old one. 45 beautiful chimes and melodies: Offers 45 classic melodic chimes with adjustable volume control and diverse selection to meet your needs . 4 volume levels adjustable from 0dB to 90dB, which is loud enough for older people to hear; enjoy pleasant melodies every time someone rings your doorbell. The LED indicator gives you a visual form of notification (a great feature for the hearing impaired). IP44 Waterproof: IP44 Waterproof Transmitter design, made of ABS, non-toxic, safe and recyclable , which can work in temperatures between -20 and 65, and withstand various harsh weather conditions, sun, 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 receivers plug-ins included, do not interfere with other equipment in your home or that of your neighbors; ensures that you will never miss a visitor, even if you are a few rooms away or on a different floor. Ideal for large homes, warehouses, offices, etc. Easy to Use: Practical and easy-to-use design for a 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. All wireless doorbells can be re-paired and controlled together." Sold by grid cool store