Abstract: A pair of cooperating resilient clamping heads of a fastener, removeably clamp edge portions of flexible sheets together, the clamping heads being themselves integrally joined together by a flexible strap. The inner surface of one head is provided with a transverse recess having spaced, opposed, inwardly converging, flanges between which are received the inwardly diverging, opposed surfaces of a locking lug removeably recessed in the recess. The lug and recess have conforming curved linear surfaces which frictionally hold the flexible sheets together. The fasteners are manufactured by extruding a continuous plastic sheet provided with a thin central portion and thicker side areas. The side areas have curve linear portions for forming the conforming recess and locking lug areas. The extruded sheet is cut at transversely spaced portions to provide the fasteners.