The Siemens 3RT1044-3AV00 is a SIRIUS size S3 power contactor — screw-type terminals on the main circuit, rated for motor switching up to 37 kW at 500 V and 18.6 kW at 690 V.
The 37 kW rating at 500 V is the AC-3 motor-switching figure — that's the real-world number for sizing across a pump, fan, or conveyor. The front is IP20 with the cover or box terminal installed; the terminal area itself is IP00, so panel builders need to account for clearance and creepage distances inside the enclosure.
Main circuit terminals accept solid conductors from 0.25 to 2.5 mm² (two per clamp) and stranded from 10 to 50 mm² (two per clamp). The auxiliary/control circuit takes 2x 0.25–2.5 mm² solid or 2x 10–50 mm² stranded. All are screw-type — no special tooling needed, but torque to the manufacturer's spec on the nameplate.