The Siemens 3SE3120-F is a position switch from the 3SE3 series, fitted with an angular roller lever actuator. It's the part you reach for when a machine door, guard, or linear slide needs a reliable end-of-travel or presence signal. The slow-action contacts — one normally open, one normally closed — break cleanly at the switching point, rated for 10 A at 500 V AC. That's enough for direct switching of small contactors or PLC inputs without an interposing relay.
Where it lives on the line
IP67 protection means the switch body and the roller lever seal against washdown and dust ingress — fine for food processing, packaging lines, or outdoor conveyor sections. The M20 x 1.5 cable gland entry is the standard European metric thread; mates with common cable glands without adapters. Dimensions are 38 x 40 x 122 mm, so it fits the same footprint as most 3SE3 and 3SE5 switches — a straight swap if you're replacing an older unit.