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 | 1 receiver | Black This Nedis Wireless Doorbell Set consists of a battery-powered bell push and a plug-in indoor unit. Because you can simply plug the indoor unit into the wall socket, you never have to change the batteries.