. . . "Outwardly extendible recess engagement element 4808 is preferably an integrally formed element made of metal, such as spring steel, and includes a generally hollow cylindrical portion 4810 formed with a plurality of axially extending slots 4812, which extend from a location spaced from a top edge 4814 of the cylindrical portion 4810 towards and through a generally radially outwardly extending disk" .