Where this limit switch actually fits
The XCMD2121L1 is a Telemecanique-format limit switch listed at 240 Vac under the Limit Switch Accessories heading, sold through the Square D Safety & Sensors subline of Schneider Electric. Limit switches in this category ride on machine guarding and conveyor position-feedback loops — the 240 Vac coil-side rating means the contact block interfaces directly with standard North American control-circuit voltage without an interposing relay.
Procurement trace and order codes
UPC 12 Digit 389118046309 anchors the factory pack and the duty of a Square D Safety & Sensors listing — that code has to reconcile against the nameplate on the carton and the line item on the PO before the part enters the BOM, otherwise the receiving inspection rejects it.