The Siemens 3SK1211-1BB40 is a SIRIUS safety relay output expansion module, designed to add four normally-open instantaneous safety contacts to an existing safety circuit. It runs on 24 V DC and each contact is rated for 5 A at 24 V, 115 V, or 230 V — so it'll switch a motor contactor coil or a solenoid valve just fine out here in the grease. With four safety-related instantaneous contacts and a total current maximum of 12 A, it's built for expanding the safe stop zone on a conveyor line or a press guard without adding another full safety controller. The 22.5 mm width means it snaps onto the same DIN rail alongside the main safety relay, and the screw-type terminals accept solid wire from 20 AWG up to 14 AWG (1x) or 18 to 16 AWG (2x) — no special crimp tool needed.
The 5 A contact rating at 24 V, 115 V, and 230 V is a resistive load rating (AC-1 class, though not labeled as such in the evidence). That means it'll handle the inrush of a contactor coil or a small relay, but if you're switching a motor load direct, you'll need to derate. The 12 A total current maximum is the sum across all contacts — don't try to pull 5 A on all four and expect the package to stay cool. The 2.5 W power loss is the heat it dumps into the panel; in a crowded cabinet with other relays, that's manageable but worth knowing for the thermal budget. Response time is 10 ms typical, 15 ms maximum — fast enough for safety stops but not for high-speed light-curtain applications where you'd need a dedicated solid-state output. The 360 1/h operating frequency means it's rated for about one cycle every ten seconds; fine for a machine cycle, not for a rapid-pick-and-place.
The 22.5 mm width and 100 mm height with 121.6 mm depth fit the standard SIRIUS modular footprint. Fastening is screw and snap-on mounting.