to be capable of being flexed or bent sufficiently for insertion into cavity 38 that is to a marginally smaller circumferential diameter than the cavity such that receptacles 44 will be circumferentially widened sufficiently so as to more easily receive the respective gasket retaining elements 42 in this regard at least when the respective gasket sections 40 a and 40 b are flexed or bent in this manner gripping surfaces 46 bounding each receptacle 44 are configured to taper outwardly to facilitate entry or guide elements 42 into the receptacles and gripping surfaces 46 are depicted here as also include tapered lead in portions for this purpose then when the gasket section 40 a or 40 b is released the shape and resiliency thereof will cause gripping surfaces 46 on at least one side of receptacles 44 to engage surfaces 48 so as to grip and retain elements 42 in the respective receptacles to automatically and positively seat and hold the gasket section 40 a or 40 b in the cavity 38 further in this regard although opposite ends 50 a and 50 b of the gasket sections 40 a and 40 b do not contain receptacles 44 and gripping surfaces 46 and thus are not positively engaged by or retained in cavity 38 in any way because of the resilient composition of gasket sections 40 a and 40 b and a resultant tendency or memory which urges them to assume their free state straight shape ends 50 a and 50 b of the gasket sections are urged radially outwardly against the radial.