The SICK WTB8-P2131 is a photoelectric proximity sensor from the W8 series, with a visible red LED emitter and a PNP switching output. It detects objects at distances from 30 mm to 300 mm, with a 500 µs response time. The 11 mm wide housing fits tight spots on conveyor rails or pick-and-place stations, and the M8 3-pin connector keeps wiring simple — no pigtail to manage. Rated IP67, it handles washdown in food or packaging lines without a secondary enclosure.
The 300 mm maximum sensing distance covers most short-range presence detection — think box presence on a conveyor, part-in-place on a fixture, or level detection through a sight glass. The 500 µs response keeps up with high-speed lines; at typical conveyor speeds that's enough to catch a passing object without missing a beat. The PNP output sources 100 mA, enough to drive a small relay or PLC input directly. Light-ON / Dark-ON selectable via the teach-in means you can set it to fire when the beam is made or broken, adapting to reflective or absorbent targets.