Its 1000 V rated insulation voltage and AC-3e maximum of 1000 V mean it handles 690 V motor circuits with margin, and the 121 kW rating at 400 V 60 °C tells you the thermal headroom for a 400 V line feeding a heavy conveyor or pump.
The 121 kW at 400 V 60 °C is the number that governs real motor switching — it's the AC-3 duty rating at an elevated ambient, not a cold bench figure. At 230 V 60 °C it still delivers 70 kW, so the contactor scales down cleanly for lower-voltage lines. The 1000 V insulation voltage (rated) and AC-3e maximum of 1000 V confirm it's built for 690 V systems with full coordination headroom. The varistor surge suppressor is built in, so you don't need an external RC snubber for coil suppression on the 110-127 V AC coil.
Screw fixing to a mounting plate — not a DIN-rail snap — so plan for drilled holes and a backplate. Side-by-side mounting is allowed, which helps when packing multiple contactors in a row for a multi-motor group. The S6 frame is physically substantial: 172 mm tall, 120 mm wide, 170 mm deep — verify your enclosure depth before committing the BOM line.