Abstract: The fastener includes a stud with a post element, a cylindrical inner sleeve with inwardly extending half-hemispherical bosses immediately adjacent to outwardly extending half-hemispherical bosses, and a base element with a blind aperture. The inner sleeve is received within the blind aperture and the post element is received within the inner sleeve. The pressure exerted upon the insertion of the post element of the stud and the structure of the bosses cause the inner sleeve to cock into a locked position. The exposed edges of the inwardly extending half-hemispherical bosses of the inner sleeve engage the post element while the exposed edges of the outwardly extending half-hemispherical bosses of the inner sleeve engage the walls of the blind aperture in order to resist the subsequent withdrawal of the post element from the blind aperture.