Check the listing for details. Fluorosilicone Gabb Fuel Cap Kits. Condition: New. Listed at 19.00 USD. Also includes an aviation grade cotter pin. The manufacturers of the fluorosilicone o-rings are ISO17025 certified. This kit replaces the following Buna-N (nitrile) o-rings: MS29513-339 and MS25988/1-110.