What this limit switch is and what it's built for
The Square D / Telemecanique XCKJ161H29 is a heavy-duty, non-plug-in limit switch from the Osiswitch line, built with a ZAMAK zinc alloy body that shrugs off the grease and grit you find on a rotating-equipment route. It's rated for NEMA 1/2/4/12 and IP66 enclosures, meaning it'll stand up to washdown, dust, and oil spray on a conveyor line or pump skid without blinking. The contact block is SPDT with a spring-return snap-action mechanism, rated to switch 10 A at 240 VAC or 0.27 A at 250 VDC. That 10 A AC rating is plenty for pilot-duty control of a motor starter or solenoid valve; the DC rating tells you it's not meant for heavy DC loads, but it'll handle a small relay or indicator lamp in a DC control circuit.
The top rod plunger head gives you a straightforward, positive mechanical actuation — 0.08 inches of pretravel before the contacts flip, with a total travel of 0.24 inches and a differential travel of just 0.035 inches. That short differential means the switch snaps cleanly, reducing contact chatter on a cam or slide that's moving at a decent clip. Operating force is 48 oz, which is on the stiffer side for a plunger — it won't trip on vibration alone, but it needs a firm mechanical push from the actuator.
This switch carries UL and CSA approvals, and it's designed to meet EN/IEC 60204-1 (safety of machinery) and EN/IEC 60947-5-1 (control circuit devices) standards. That combination means it's accepted in North American panels and satisfies the machinery-safety requirements for European-influenced designs.