The S/P pneumatic couplers are of Japan standard, E.MC pneumatics & hydraulics has material of steel, stainless steel and zinc, of which steel pneumatic couplers are most normal. This kind of pneumatic couplers are of good quality with very good prices, very popular most in South-east Asia market. The S/P type pneumatic couplers are widly used together with tubing, air guns to finish some function.