The practical Solight Wireless Doorbell, Socket, 150m, White, Learning Code (1L43) doorbell can be used at home or at the office. The bell features 36 ringtones. The bell has a secure range of up to 150 m, making it ideal for placement on a remote entrance gate, for example. The receiver must be permanently connected to a mains socket. This is fine if you don't require the bell to be portable. Radio waves transmit the signal between the button and the bell.