Features: Main Function: The basic-design of a way check valves inhibits back flows in a line. prevent fuel from returning back to the tank and keeps it in the line. In this way, this product can perfectly solve the problem that your vehicle is hard or slows starting issues. Material: Made of aluminum alloy, stable characteristics, high reliability, anti-corrosion, superior thread strength. One-Way Check Valves Design: Arrow-marked on valves, showing fluid-flow direction, prevent fuel from returning back to the tank and keeping it in the line Easy Installation Replacement: According to the little-arrow on the valves, connect the fuel line. also, use some hose clamps which can make sure the pipes don39;t drops off. Wide Application: Suitable for many diesels/ biofuel systems / Carburetors and low-pressure fuel systems where you desired fuel to only flows one-way. Suitable for water, petrols, diesels, oil, and other fluids. Notice: 1.Actual color may be slightly different from the image due to different light effect 2.Please allow 1-3cm deviation due to manual measurement Specifications: 6/8/10/12mm Material: Aluminum Alloy Package List: 1x Aluminum Alloy Check Valves