The Festo SME-3-LED-24-K5 is a proximity switch running on 12 to 27 V DC, rated to sink 200 mA through the output. The 5 m cable gives you reach into the panel without a junction box — one less failure point on a line that's already down.
The housing dimensions are 19 x 13 x 18 mm — a compact footprint that fits tight spots on pneumatic actuators or machine frames.
