Update your semi truck or trailer with safely sealed electrical openings, with the Truck-Lite 4" 16-Gauge GPT Wire Marker Clearance Plug that ensures you're Ready for the Road Ahead. To adapt LED lamps to conventional plug harness systems while preventing dirt, moisture, or other unwanted contaminants from entering a system, this replacement device gently plugs into the powered space to protect the device. Manufactured with tin-plated brass terminals for improved conductivity. FleetPride is your First Click in Heavy Duty.