The Model DTG Safety Edge Transmitter is compatible with all of Delta-3 products. In a typical installation, the DTG is mounted on a motorized gate, door or barrier arm and wired to a standard exterior safety edge sensor which presents a closed circuit across the connecting wires when an object is hit during the closing of a gate.FeaturesSafety edge transmitterActivates one Delta-3 receiver for remote stop or reverse safety edgeNo cables or coiled wiresMounting screws (4) suppliedPower: 9-volt batteryCodes: 256 (set by dip switches)RF frequency: 310 MHzDimensions: 4.28" W x 2.875" H x 2.25" D