The Siemens SIRIUS 3RT1355-6AF36 is a size S6 contactor with an AC coil rated 48 to 130 V, consuming 4 VA at both 50 and 60 Hz. Mount it on a vertical surface with screw fixing; the enclosure allows ±180° rotation and up to ±30° tilt forward or backward.
The 4 VA coil draw tells you the control transformer size — at 48 V that's under 0.1 A, so a small 50 VA transformer can run a handful of these in parallel. The 48–130 V AC coil range covers common control voltages in North American and European panels; the pickup threshold is 0.8 × rated (about 38 V minimum), so it stays pulled in through brownout conditions down to that level. The auxiliary contact ratings (3 A at 24 V DC, 0.55 A at 110 V AC) are the practical limits for signaling a PLC input or driving a small pilot light — stay under those and the contact will outlast the panel.