SPOC 1/4-04 is a model number of 1/4" O.D tubing x R 1/2 male thread hex socket head male connector stainless steel push in air fittings. Its round shaped body and internal hexagon allows it to be installed anywhere space is limited. Connect 1/4" pneumatic tubing and installed to R, PT, BSPT 1/2 female thread. 1/4" x R 1/2 stainless steel round male straight push to connect air fittings are composed of stainless steel body with stainless steel collet & FKM( Viton) seal, fitting for high temperature and corrosive environment.