Cloth windlace is best described as a rope like material with a flat piece attached to it.  That flat piece is used to attach the windlace to the classic car tack strip.  Windlace was used on classic cars from the 1920s through the 1960s.  The purpose is to cut down on the windlace in cars as they travel down the road.  Windlace must go in before the headliner.