DIN-rail mount, so it snaps into any standard panel enclosure.
How it sits against the 2-pole sibling
The closest functional peer is the S202M-C16 — same 16 A, same Curve C, same 6 kA AC interrupting rating. The difference is poles: S201M-C16 is 1-pole (switches one line), S202M-C16 is 2-pole (switches both line and neutral or two phases). If your panel was laid out for a 2-pole breaker, the 1-pole won't drop in without rewiring the load circuit. But for single-phase branch protection, the S201M-C16 is the correct fit.
