... .volume control and mute 2.Distance 40 meters 3.Stable RF frequency,433Mhz 4.Water drip proof design door bell& doorbellWireless Doorbell ... :- Supply: 230VAC, 50Hz - Rating (socket outlet): 16A 3680W max - Frequency: 433MHz Wireless Doorbell Transmitter Features :- water drip proof design - random coding ... :- Battery: 2 X 1.5V (LR44/AG13) button cells - Frequency: 433MHz