Top Gun Customz Diesel Auxiliary Install Kit is designed to connect your auxiliary diesel fuel tank to your truck's fuel filler neck in order to provide consistent gravity feed of fuel. The kit controls the fuel level going into your OEM tank to prevent overfill. Easy installation. Kit contents: hose, clamps and fittings and is intended for diesel fuel only. Aluminum Tee 1.38 inch Inner Diameter, 1.50 inch Outer Diameter.