Mere informationShading set consisting of 3 different types of lenses: Corridor, 90° and 180° shutter ¦ Shutters mountable directly to the front of the sensor in 4 different positions 0°, 90°, 180° and 270° angle relative to the sensor device ¦ No disturbance of light measurement or IR receiver signals ¦ Material transparent Lexan 923 with polished surface finish ¦ Shutters made for one time use, once installed removal may damage the shutter and sensor lens!