It you are purchasing or own an EMX NIR-50 retro-reflective photo eye, this is an additional purchase of a hood that the photo eye can be placed inside.
The NIR-50 photo eye works on reflecting the safety beam back to the receiver/transmitter unit. If the beam is not reflected properly the system will react as if there is an obstacle.
The hood keeps rain and other debris (such as bird waste which has a way of falling on any surface you do not want it to) from distorting or blocking the photo beam. This also helps to keep midday sun, the most intense sun rays, from glaring off the reflector and disturbing the beam's reflection.
QB ID: NIR-HD