This light barrier uses the IC U2531B and works with invisible infrared light beams. Transmitter and receiver included! Ideal for alarm systems, automatical animal picturing, remote control for garage doors, etc. With incorporated infrared filter for day operation! Operating voltage transmitter 9 V/DC Operating voltage receiver 12 V/DC Transmitting power adjustable Relay contacts 1 x ON, max. 3 A Board dimensions transmitter approx. 23 x 45 mm Board dimensions receiver approx. 55 x 44 mm