The ENER-J Wireless Kinetic Doorbell is an innovative and maintenance free entry solution that requires no batteries for either the transmitter or the receiver. The outdoor push button generates its own power through kinetic energy with every press, sending a stable signal to the stylish UK plug in chime unit. Featuring 38 high quality ringtones and four adjustable volume levels, this system is designed for quick setup and long term reliability, offering a modern alternative to traditional wired doorbells without the need for complex electrical work. - ENER-J Wireless Kinetic Doorbell & Plug In Chime White 240V