semi rigid pipes in which the elastic retaining ring for holding a pipe in the connection is seated in a flanged ring portion of the stop ring that limits opening movement of the spring taps of the retaining ring and a supporting ring is located between an end face of the flanged ring portion and a plurality of shoulders spaced around the periphery of the entrance to the connection to hold the retaining ring in place application_number US 31473989 A description the plug connection illustrated in the drawings is composed of a housing part 1 having a passage 2 for the flow through of a fluid and several cavities successively larger in steps for receiving a semi rigid pipe 3 such as a plastic gasoline feed pipe as well as the connecting parts described in detail below the inside diameter of the innermost or first cavity 4 corresponds to the outside diameter of the pipe 3 and has a shoulder 5 serving as a stop for the pipe 3 and limiting its depth of penetration a second larger cavity 6 holds a sealing ring 7 the inside diameter of which is somewhat smaller than the outside diameter of the pipe 3 the axial movability of sealing ring 7 is limited.