Abstract: A light grid which has a housing made from an extruded profile. An electronic component plate is movably insertable into the interior of the housing and carries the optical components of an emitter unit or a receiver unit, respectively. The housing has a support plate and an intermediate web which connect spaced-apart side walls of the profile and include openings. The support plate also has openings into which corresponding optical function elements are inserted. The openings in the intermediate webs serve as apertures. To precisely align the component plate with the optoelectronic components thereon relative to the housing, positioning pins are inserted through openings in the support plate and the intermediate web and which further engage locating holes in the component plate.