The Festo SMEO-4U-S-LED-24 B is a magnetic reed proximity sensor — a cylinder position feedback device for pneumatic actuators. It switches on when the piston magnet passes, with a normally open output and an on-time of 0.5 ms, meaning it catches fast-moving cylinders without missing a stroke. The 0.2 mm repetition accuracy tells you the piston stops within that band cycle after cycle, which matters for pick-and-place or cut-off gates where repeatability drives scrap rate.
Mounts via the T-slot on Festo cylinders — no bracket needed. The M8 plug (3-pin, straight) mates to a standard M8 cordset; verify the pinout matches your I/O card before terminating. Supply voltage runs up to 27 V DC, so it sits comfortably on a 24 V nominal control bus with headroom for ripple. The LED indicator on the body gives a quick visual on state during commissioning without a multimeter.