Infrared LED emitter Silicon phototransistor sensor Snap-in mounting Variable sensing distance over 36” (91.4 cm) Low profile package 24” (61.0 cm) wire leads The OPB100Z series consists of an infrared LED (OPB100-EZ) and phototransistor (OPB100-SZ) in separate plastic housings. The low cost, snap-in design requires no screws or other mounting hardware for ease of installation. The emitter and sensor are not apertured, which allows separation distances in ex.