The Siemens 3RH1422-1BA40 is a SIRIUS auxiliary contactor in size S00 — a compact 57.5 mm wide, 90 mm tall, 72 mm deep block that snaps onto a DIN rail or screws into a panel. It carries two normally-open instantaneous contacts rated for AC-12 duty at 10 A maximum, with a 12 V DC coil that draws 3.2 W closing and holding. Its job is to switch control signals — not motor loads — in a panel. The AC-12 rating (resistive loads at the same voltage as the coil) means it handles relay coils, PLC outputs, and indicator lamps. The 10 A at 24 V is the ceiling; at 230 V it's good for 6 A, at 400 V for 3 A, at 500 V for 2 A, and at 690 V for 1 A.
Mounting and wiring in the panel
Mounts by screw or snap-on onto a DIN rail. That matters when you're squeezing it into a crowded enclosure and need to reorient the coil terminals. Wire terminations accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid — so you can land two conductors per clamp up to 4 mm².