Square D (Schneider Electric) XUZC24 Sensor Retroreflector. Telemecanique Osisense Square D Sensor Retroreflector, 24 mm L x 21 mm W Size, 150 deg F. Additional Description: SQD -XUZC24 PHOTOELECTRIC SENSOR REFLECTOR 24X21MM+OPTIONS. Catalog Description: Photoelectric sensors XU, accessory for sensor, reflector, 24 x 21 mm.