Vehicle Loop Detector, 24V with HarnessVehicle Loop Detector Indoor Enclosure (NEMA 1) Enclosed, requires separate 24VAC power. Wiring harness with plug for detector included. OPEN only (all LiftMaster operators) or SAFETY HOLD OPEN only (operators with type B2, T, TS or T1 control wiring) when vehicle passes over loop wire. Requires a loop of wire embedded in the ground to connect to the detector. Requires 2 wire output connection to door operator and 24VAC power.