About this item Material: Aluminum Alloy. The weld on filler neck and cap is suitable for oil tanks, fuel tanks, water tanks, dry fuel tanks. This aluminium alloy fuel cap features an O-Ring on the cap and compliant with aviation hose coupling requirements. Package Included: 1 x Silver Fuel Tank Cap,1 x Silver Flange Cap,1 x Seal O-Ring Bore: 50mm / 2″, Neck Thread Size: M58 x 2, please buy according to your needs and the size in the picture.