1/8 4MM 1/4 6MM 5/16 8MM 3/8 10MM 1/2 12MM 9/16 16MM Non Return One Way Fuel Check Valve Aluminium Alloy Petrol Diesel Application: For Carburetors and low pressure fuel systems(Petrol / Diesel /Fuel) Features and Benefits: The one-way valve, made with high-quality materials, and also with advanced technology and equipment. Hand Pump is screw onto the suction valve of oil transfer/feed pump, when the engine is at rest, from diesel fuel tank pump into the oil transfer pump. Prevents fuel from returning back to the tank and keeps it in the line. Dimensions Material: Material: High Quality Aluminum Alloy Size: 4mm (1/8 ),6mm(1/4''),8mm(5/16''),10mm(3/8''),12mm(1/2''),14mm(9/16'') Color: black.silver Package Included: 1x Fuel Check Valve. (100% Brand New Never Used Or Installed) All items are Brand New unless stated otherwise on the listing. We sell DIY (Do It Yourself) Items with a few exceptions. We take no responsibility in teaching you how to install. Professional installation is strongly recommended.No instructions included!