Enables the technician to isolate the Master Cylinder from other brake components It tests whether the internal seals are leaking or in good condition. Kit has 26 machined aluminum plugs to fit most domestic and import vehicles and includes enough plugs to meet latest master cylinder designs. SAE sizes include: (2) 3/8-24, (2) 7/16-24, (2) 9/16-18, (2) 9/16-20 and (2) 1/2-20 Metric sizes: (4) M10x1.0, (4) M10x1.25, (2) M11x1.5, (2) M12x1.0, (2) M12x1.5 and (2) M13x1.5.