What the category tells you about deployment
The XCKD2521P16: Medium Duty Limit Switches are the workhorse class for general-purpose machine guarding and position detection in dry indoor environments. They are not rated for submersion or high-pressure washdown — that would be a heavy-duty or IP69K variant — but they handle the dust and occasional splash of a typical assembly line or packaging cell. The Square D Sensors & Safety branding places this in the Telemecanique lineage, which means the mounting hole pattern, actuator travel, and electrical rating follow the established XCK form factor used across hundreds of thousands of panels. If you are replacing an existing XCK-series switch, the footprint and wiring convention are consistent within the family.