Seal Retainer Ring Valve Parts Machined directly from Round Bar NC Machining Oil ... and steel plate, Drilling, Milling, Turning, Boring, Slating, Grinding,, NC/CNC Machining etc.4) Tolerance is controlled by CMM Machine.5 ... : ASTM, BF,BS, JIS, UNI, ANSI, ISO etc. Seal Retainer Ring