Pneuflex SPC 04-G01 is 4mm tubing, BSPP, G 1/8 male connector stainless steel push-in fittings with O-ring thread seal, one of common push to connect fittings used in corrosive environment where brass nickel-plated and acetal fittings are banned, available used with PU tubing, nylon tubing, Teflon tubing...