Easy Turn Fill Caps

Turn heads while working on your race car with Pro-werks’ signature Easy Turn Fill Caps. Once you've added one these great looking components, you may find yourself checking fluids more often, just to get your hands on the caps again!

These lightweight, non vented Pro-werks Fill Caps feature deep finger notches for a positive and comfortable grip. The 6061-T6 American melt billet aluminum is CNC machined for accuracy, and is available in your choice of either brilliance anodized black, red, blue, or silver, as well as micro-polished aluminum finish.

Our design uses a radial squeeze action on a Buna O-ring for a secure seal. Precision machined quick-start coarse threads make using our caps a breeze.

Pro-werks’ mounting bungs are crafted from steel, aluminum or stainless and available in both weld-in and bolt-on styles.

Easy Turn Fill Caps are available many sizes and mounting configurations to fit almost any application.

Popular uses for Easy Turn Fill Caps include:
  • Custom-fabricated tanks
  • Fuel cells
  • Rear End housings
  • Valve covers
  • Overflow tanks
  • Ice boxes for intercoolers
  • Ballast tanks
  • Inspection viewing ports

Proudly Made in the USA.


"I use your bolt on caps and bungs on my carbon fiber Cummins common rail valve covers. Love the quality. Thank you."
             Randy Davis, Owner of OldSkoolFab, Inc.



"I upgraded by fuel cell to an Easy Turn fill cap assembly. It wasn't long until all my friends did the same. Great product!"
             As shared with us at the
PRI Show


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