Transfer Tank Cap Vented Diesel Fuel Cap,Gas Venting Pressure Tank Lid for 2 ... About this item Fitment: Transfer tank vented cap replace for Dee Zee Fill-Rite venting pressure tank cap and fit for standard 2" NPT threaded tank bung base. Diesel tank cap works well for ground, farm, commercial and distillate tanks, such as transfer tank, fuel tank, gas tank, diesel tank, auxiliary fuel tank, mobile fuel tank and weather guard tank. Both Directions Vent: When loosing the cap, the transfer diesel tank cap vent pressure inside the tank to outside and release dangerous vapor build up to prevent over-expansion of the fuel tank. And allow air into the diesel transfer tank to prevent vacuum forming and collapse the tank when you draw out fuel. Prevent Leaking : Fuel transfer tank cap with spring loading and inside gasket is seal when tightly closing to prevent leaking and excess gas vapor venting even drive in road. Easy to Use: Align the transfer tank fuel cap with the notch, push down and clockwise twisting to tighten the diesel tank cap all the way. To remove transfer tank cap, counter-clockwise twist slowly to the notch to vent pressure. Push down and twist to lift pressure vent cap and remove. Heavy-duty Diesel Tank Cap : Made of high quality materials featuring waterproof and corrosion resistance to long term serve your diesel tank. The transfer tank vented cap package only includes a removable transfer tank fuel cap