The Siemens SIRIUS 3RT1034-1AC20-ZW95 is a size S2 power contactor with a 24 V AC coil rated for 50/60 Hz.
The AC-3 switching capacity at 400 V is 15 kW, which means this contactor is sized for a 15 kW three-phase motor on a 400 V line — typical for pumps, fans, or conveyors in a distribution panel. The AC-1 resistive rating at 690 V is 10 kW, covering heater or lighting loads at higher voltage. Coil draw at 24 V AC is 10 A inrush, which the control transformer must be sized to handle; the pickup dropout range of 0.8–1.1 x rated voltage at 50 Hz and 0.85–1.1 at 60 Hz means the coil holds in reliably even with a sagging control bus.
The solid wire capacity is 2x (0.5–1.5 mm²) and 2x (0.75–2.5 mm²), max 2x (0.75–4 mm²). Stranded wire takes 2x (0.75–25 mm²), and solid or stranded combined is 2x (0.75–16 mm²). That covers most motor feeder cables up to 25 mm² stranded — no need for special lug adapters.