The Siemens 3RT10441AK600ST0 is a Size S3 contactor from the SIRIUS family, rated for 65 A at 120 VAC coil voltage, 3-pole, with screw terminals and a modified shunt ring. Its AC-3 duty rating of 30 kW at 400 V means it handles motor switching for loads up to that power — think conveyors, pumps, or compressors in a standard 400 V three-phase line. The 120 VAC coil (110 V 50 Hz / 120 V 60 Hz) pulls in reliably across that range; verify your control transformer taps if you're running at 50 Hz.
Size S3 frame snaps onto a standard DIN rail in the panel — no adapter plate needed. Screw terminals accept up to the rated conductor size; the modified shunt ring is a factory-fit option that reduces arc-blow on high-inrush loads, so if you're switching a transformer or a capacitor bank, that ring is already in place. Coil draw at 120 VAC is modest — no separate control transformer derating for a single contactor, but watch the cumulative VA if you're ganging several on one transformer.