Photo Beams – Though beam, 12V, NC System “The GTO/PRO Photo Beams provide a “non-contact” means of entrapment protection.” The GTO/PRO Photoelectric Dual Beam Detector uses dual beam and through beam technology to reduce false detections when detecting obstructions. When the beams detect the presence of a moving object, the detection will cause the gate(s) to stop and reverse to the fully open position. As long as the beam is obstructed the gate(s) will remain open. Not compatible with solar powered gate operators. This product also requires "Low Voltage" wire.