Ulive Wireless Doorbell, Operating Range Over 500ft, 36 Chimes, Adjustable Volume, Water & Dust Resistance Level Ip44 Stylish modern design with sleek surface, no dust accumulation and easy to clean; Personalization of your door chime with 36 chime options and 4 levels of volume adjustable from 20dB to 80dB. Simple and wireless installation : Door Chime (Receiver) to be plugged into electrical outlet; Push Button (Transmitter) to be mounted by adhesive tape. Push Button may also be mounted by screws if needed. All accessories are supplied in the package. Long operating range over 500ft (maximum range of 1000ft in open area), powerful penetration ability ensuring wireless signal transmission through walls. Transmitter is rated IP44 and may be installed outdoor. (IP44: protection against solid of diameter &gt;1mm and against splashing water. ) Extremely low power consumption, neglectable effect on your electricity bill. For transmitter, 1 pc of 12V23A battery (included) may last for more than 1 year (15 times pushing/day)