An elongate resilient section at the closure edge of a closure movable to close an opening contains at least one electrical switching strip 11 which is arranged in associated hollow cavity (13, 14; 112) close to the elongate securing block (20; 120) used to secure the resilient section to the closure edge. The resilient section is so constructed that the electrical switching strip or strips (11; 11, 12) respond(s) not only to compressive forces acting in the direction of closure but also to forces acting sideways on the resilient section.