10pcs/lot ST131 on-beam photoelectric switch slot photocoupler slot photoelectric intermittent sensor slot width 3mm
https://www.vogueparade.com/shopping/EN/150412/1/1005003420112180/10pcslot-st131-on-beam-photoelectric-switch-slot-photocoupler-slot-photoelectric-intermittent-sensor-slot-width-3mm//