Abstract: The improvement relates to fluid couplings utilizing components interconnected by an elongated pin or staple wherein insertion of the staple after assembly of the coupling parts maintains the parts in fluid tight relationship. The invention includes the forming of fluid coupling members permitting accomodation of staples having various cross sectional configurations, and the staple of the invention is of a D cross sectional configuration providing optimum resistance to fatigue failure, improved tensile strength, and consistent retention within the fitting under operative conditions.