anodized aluminium oil tank opening filler cap. This is designed to thread into a tank with SAE type Oring Fittings. We think the threads a 1 1/2″. The cap then has a quick release cap that is attachede to the fitting with a chain. This would be a super trick part on a race car tank. The fitting that threads into the tank is set up for safety wire as the holes are predrilled. Orignal appliaction was military heavy armored vehicles. A super trick part here Made by Eaton Aerospace PN#B6542PA or XM6349-2 or 12273121-2 NSN 5342-01-074-3763. Save $$$$$$$ buying from us. L2C4 10326