What it is — and what it bolts to
The 3RH2911-1GA13-Z X95 is a front-mounted auxiliary switch block carrying one normally open and three normally closed contacts — 1 NO + 3 NC, wired to terminals 53/54, 61/62, 71/72, 81/82. Screw terminals, physically coded. That physical keying means it only fits the 3RH2140 and 3RH2440 contactor relay frames per EN 50011; it won't mate with the 3RH21 or 3RH24 base units of different sizes. If you're swapping a failed block on a 3RH2140 or 3RH2440, this is the direct drop-in.