Pre-assembled coupling assembly with flexible hose adapter

A method for using a pre-assembled coupling assembly, the method comprising:

• aligning an inner end of an end piece with a first end of a coupling with the coupling in a relaxed position, the coupling defining a second end opposite from the first end, the coupling defining a coupling bore extending from the first end to the second end, the coupling comprising a gasket positioned within the coupling bore, the gasket being relaxed and uncompressed in the relaxed position, the end piece defining an outer end opposite from the inner end, the end piece defining an axis extending from the inner end to the outer end, the end piece defining a groove, a sealing surface, and a stop lip comprising a circumferential gap, the sealing surface axially positioned between the stop lip and the groove, the stop lip positioned at the inner end;
• and
• axially inserting the inner end of the end piece into the gasket comprising:
• stretching a sealing ridge of the gasket radially outward over the stop lip;
• axially aligning the sealing ridge with the sealing surface;
• and
• positioning a radially innermost portion of the sealing ridge radially inward from a radially outermost portion of the stop lip to retain the coupling on the inner end when the coupling is in the relaxed position.