(under subclass 200) Device wherein the closure: (1) is pre-stressed so as to normally assume a warped shape and must be force toward an unwarped position during application, the inherent force trying to assume the pre-stressed warped shape being the force which holds in the closure in place; (2) is normally unwarped or warped in shape while unapplied and is warped in or further warped during application, the force of trying to assume an unwarped or less warped position being the force which holds the closure in place.
