PCF 04-M6 female connector push to connect fitting is used to connect 4 mm O.D tubing to M6 x 1 metric parallel male stud thread in an inline configuration. Outside hexagonal wrench tightening. Oval or round release ring helps to connect tube easily by manual, no special tools required. Have abrasion resistance, light weight, and resistance to crushing and cracking, compressive and corrosion resistant, good sealing performance and long service life.