The Siemens 3RB3046-1UX1 is a SIRIUS solid-state overload relay in the S3 frame size, rated for 50 A continuous thermal current (Ith) and 50 A at both 480 V and 600 V. The relay is designed for stand-alone installation, not a motor-starter combo block, so you'll mount it separately on the DIN rail and wire the main current circuit through its straight-through transformers.
The S3 footprint is 70 mm wide × 106 mm tall × 124 mm deep — that's a standard 4-module-wide DIN-rail footprint, so it'll fit a typical 600 mm enclosure backpanel without crowding the gland plate. The screw terminals accept 2× (0.25…1.5 mm²) solid or stranded, and the screwdriver spec is Pozidriv PZ2 with a 5–6 mm shaft diameter — keep that bit on the cart; PZ2 is less common in US panels than Phillips #2. The integrated auxiliary switch (97/98) signals the tripped state — the note on the part is literally for message "tripped". That contact is rated 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, so it can drive a PLC input or a small pilot light directly. Shock resistance is 8g / 11 ms for the signaling contact in the tripped position, 15g / 11 ms for the main body per IEC 60068-2-27; vibration per 1–6 Hz at 15 mm amplitude, 6–500 Hz at 20 m/s² for 10 cycles. That's robust enough for most industrial machinery but not for a shaker table or a mobile application.