Abstract: A retainer employs a flexible arm with an internal rib. In another aspect of the present invention, a retainer has at least one generally triangularly shaped projection laterally extending from an arm. A further aspect of the present invention retainer provides a laterally enlarged member, a trim panel-retaining head and stem, a central post, one or more flexible wings flexibly spanning between a tip of the post and the laterally enlarged member, and an internal rib and/or at least a pair of generally angular extensions flexibly extending from each arm.

Abstract: A fastener can be of the general type inserted into a hole in a panel. Such a fastener may include at least two arcuate hinge segments and a corresponding number of wings extending divergently away from the hinge segments, each hinge segment having two arcuate surfaces spaced apart from the center post. Such a fastener may also include wing-arms that extend convergently towards a region beyond the distal end of the center post and that collectively take on a beak configuration, e.g., ends of the wing-arms taking on a ball-and-socket conformation.