The Siemens 3RH1131-2JB40 is a SIRIUS coupling relay designed for switching auxiliary circuits — think signal isolation between a PLC output and a contactor coil, or interposing between a safety relay and a motor starter. It is not a main power contactor; its job is switching control loads up to 10 A in AC-12 duty (resistive loads and solid-state outputs). The 24 VDC coil draws 2.3 W both on pickup and hold, which is useful to know for power supply budgeting in a panel with multiple relays.
Zero side clearance is required, meaning you can butt it against adjacent devices without derating. Screw terminals accept 2x 0.25 to 2.5 mm² solid or stranded wire.
The headline rating is 10 A at AC-12 (resistive loads and solid-state outputs). AC-12 is the category for switching resistive loads and optocoupler inputs — common in control panels. The built-in diode surge suppressor across the coil means you don't need an external flyback diode for DC switching; just watch polarity. Three instantaneous NO contacts (no delayed or make-before-break) give you three isolated signal paths from one coil.