OBP 1.000" bore, non-integral hydraulic master cylinder (25.4mm bore). Good quality alloy master cylinders, directly interchangeable with Girling master cylinders and others from Tilton, AP Racing and Alcon, although fittings and dimensions may differ depending on the manufacturer. Suitable for all OBP bias pedal boxes and hydraulic handbrakes, as well as similar products from other manufacturers. Standard 95mm long, 5/16" UNF threaded push rod size. Distance from cylinder mounting face to end of cast aluminium body 116mm. Inlet port: 7/16" UNF convex, Outlet Port: 3/8" UNF concave.