This is a Siemens SIRIUS power contactor, order code 3RT1045-1AB00-1AA0, in the S3 frame size. The AC-2 rating of 37 kW at 400 V covers slip-ring motor starting.
The 70 mm width and 146 mm height fit a standard panel grid; depth is 139 mm including the arc chamber.
Terminal specs and wiring
Solid wire: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Stranded: 2x (10 to 50 mm²). That's a wide range — fine wire for control circuits, heavy cable up to 50 mm² for the power loop. IP20 on the front with the cover or box terminal installed; the terminal body itself is IP00, so keep live parts inside the enclosure.