Abstract: An entrapment prevention device for ensuring that people or obstacles do not become trapped in the path of automatic doors, windows and the like features an elongate sensor which can be fitted along an edge of an opening or of a closure member adapted to close the opening.The sensor features a pair 11 of electrically conductive bands 13 and 14 which are held spaced apart and facing each other by insulating strips 17 with the pair of bands being wound in helical form round a core 12 to form an elongate structure. A series of transverse slots are provided in the surface of the radially outer band 14 so that the remaining web portions 15 can be easily deflected by light contact pressure to electrically contact the radially inner band 14. This electrical contact is sensed by a monitoring circuit 24 which energizes a relay 26 to stop or reverse the automatic drive. The pair of bands 11 is surrounded by an outer helically wound resilient cushion 18 and is enclosed in a continuous outer sleeve 19.