A. 300m remote control range, with 36 ringtones and 4 levels of volume to meet your needs for different occasions B. Comes with the receiver, will not interfere with other equipment in your home or those of your neighbors, ensures that you will not miss any visitors, even if you are several rooms away C. Convenient and easy-to-use design for a better user experience D. Simply get the bell plugged into the socket and tear off the tape of the sensor and stick it on the door frame E. Waterproof design, it is a useful accessory for home, office, store, etc F. Specification: G. Transmitter: with indicator light, press the light to turn it on H. Receiver: Just plug it in, the bell rings and the light is on I. Music alarm: 36 music optional J. Volume: 4 levels of volume adjustable (can be adjusted to silent mode) K. Transmitter power supply: 1pc 12V 23A battery for each transmitter (battery not included) L. Receiver power supply: AC 110V-220V M. Scope of application: office buildings, home stores, factories, etc