The Siemens 3RH1911-1FB22 is a SIRIUS auxiliary switch block with 2 NO + 2 NC contacts, screw-type terminals, and a 10 A maximum rating. It snaps onto contactor relays and power contactors in the S00 frame size, following the EN 50005 contact arrangement.
Snap-on mounting to the contactor or contactor relay — no tools for the mechanical fit. The screw terminals accept 2x (0.5...1.5 mm²) or 2x (0.75...2.5 mm²) with core end processing, or 2x (20...16) and 2x (18...14) AWG. The 41.5 mm depth and 36.5 mm width fit the S00 contactor footprint — no extra DIN rail space beyond the contactor itself.
The contact ratings cover a wide voltage range. At 24 V AC-15 it's rated 10 A; at 230 V AC-15 it's 6 A; at 400 V AC-15 it's 3 A. For DC switching at 24 V it's 6 A, dropping to 0.3 A at 220 V.