The residual valve is used in disc drum brake applications, provides help for braking valve. Made of metal, it is very professional and reliable, can be used for a long time. The blue residual is used for the front disc and the red residual pressure should be used for the rear drum to prevent fluid from flowing back without causing the brakes to drag. Features -Color:Rosy -Material:Metal -Size:6.50X2.00X2.00cm/2.55X0.79X0.79in -Note: 10 psi -Good Helper: The residual valve is used in disc drum brake applications, provides help for braking valve -Sturdy Structure: It is made of sturdy metal, very professional and reliable, and you can use it for a long time -Great Choice: The residual is used for the front disc and the residual pressure should be used for the rear drum -Fine Workmanship: Features by high performance, resistance to corrosion, light weight and easy operation -High Versatility: Can be used for most kinds of vehicles, you will have a satisfying experience Package list: 3 x residual brake valve