Whenever two bare wires have contact with water, the light emitting diode will light up. The device is suitable to release alarm in case of overflowing rain barrels and gutters. Operating voltage: 9 V/DC. As accessories is available the kit B197 - Relay card 12 V/DC, which could be connected with this kit and could switch through the relay contact other devices (e.g. pumps) up to current consumption of 3 A. Operating voltage 9 V/DC Power consumption rest (without water contact) < 10 uA, LED shines approx. 15 mA Indication of water via LED Size of board approx. 45 x 16 mm