Inlet Size: M12 x 1.5 Male Flare, Outlet Size: -6 AN Male Flare (9/16 x 18), One Way Check Valve with Spring Design Inside Parts, Made of Aluminum Alloy Positive Seal, High flow capacity and Positively Stops Fluid From Returning ANTI-LEAK, ANTI-BACKFLOW -- When installed correctly (check the arrow on the piece to know the correct side.Suits Fuel Pressure Systems, Oil Pressure Systems, Transmission Cooling lines, Air Systems, Fuel Cell Breather (With Cracking Spring Removed) Black anodized finish,Opening housing is secured with an O-ring for a perfect seal & to stop it coming loose with vibration.These one way poppet valves perfect all fuel applications Precision machined to ensure precise thread engagement Male flare EFI check valve: ANTI-LEAK, ANTI-BACKFLOW -- When installed correctly (check the arrow on the piece to know the correct side)Ensures that the water and air circulations are consistent and going in the right direction without any backflowIdeal fuel systems where a check is required inlineComes installed with a viton o-ring which is suitable use with unleaded race fuelsAn o-ring to suit Methanol is also included with the check valveOne-piece, CNC-machined T6061 billet aluminum design ensures the most direct path for unrestricted and redirected flow. Lightweight and compact for tight confines, these pro flowing fittings attach directly to hose ends without adapters. Provides maximum flow and do not require sealing compound or Teflon tape, one-piece reusable mandrel-bent fittings.Great for any liquid or gas application where a high-flow splitter is needed.Hard-anodized coating is compatible with alcohol, exotic fuel-additives, water and oil