Wireless doorbell set Mains power supply | 100 - 240 V AC 50/60 Hz | 1x 23A 12V | Volume: 110 dB | Signal range: 150 m | IP55 | Adjustable volume | 58 melodies | 2 receivers | Black This Nedis Wireless Doorbell Set consists of a battery-powered bell push and two plug-in indoor units. Because you can easily connect the indoor unit to the wall socket, you never have to change the batteries.