The Siemens SIRIUS 3RH2911-2GA31-ZW97 is a front-mounted auxiliary switch block for contactor relays, delivering 3 normally-open and 1 normally-closed contact set (3 NO + 1 NC) with spring-loaded terminals. It snaps onto 3RH2140 and 3RH2440 contactor relays only — physically coded so it won't mate with the wrong frame. Rated 10 A maximum, with the AC-15 switching capability at 690 V rated at 1 A, this block handles pilot-duty and control-circuit loads in a panel.
Surge voltage withstand is 6 kV, which covers most installation categories up to 400 V line-to-line. Mechanical life is 10 million cycles typical, so it outlasts most contactor relays it rides on.
Snap-on mounting to the contactor relay front — no tools, but the physical coding means it only fits 3RH2140 and 3RH2440 frames. Spring-loaded terminals accept 2x (0.5 to 2.5 mm²) without ferrules, or 2x (0.5 to 1.5 mm²) with ferrules. AWG equivalent is 2x (20 to 14). Strip length is not stated, but 8 mm is typical for spring-cage blocks in this class.