ACS new style fuel cap 10455.
Made in USA
These fuel caps are not a direct replacement for the earlier ACS design (which were lost inflight due to inadequate rubber seal design). The new 10455 cap outside diameter is too large will require machining to fit the ACS receiver ring. After this modification, they fit nicely.
The outside diameter of the rubber gasket in this fuel cap is approx 2-3/4" and the height is approx 1/8".