The series SE Safety edge consists of a rugged high tear resistant rubber profile, an aluminum mounting rail, a plug-in optoelectronic transmitter and receiver pair and a compatible safety controller. The design features a high reflective internal rubber surface and a self-adjusting gain optical pair whose performance is uncompromised by slight bending and predictable over the specified operating range. Units can be quickly and easily assembled (without special skills or use of adhesives) for lengths of 400 mm to 10 m. The self adjusting optical pair assure the same sensitivity and performance independent of chosen length. The mechanical design assures encapsulation of the transmitter and receiver ensuring reliable operation unaffected by environmental soiling.