The Siemens 3RT6018-1BF41 is a SIRIUS S00-frame power contactor with a 110 V AC coil, sized for motor loads up to 13 kW at 400 V at 60 °C ambient — that's the rating that governs the real-world panel temperature, not the 40 °C figure. The mechanical life of 30 million operations is typical for this class — the electrical life depends on the switching category (AC-1, AC-3, AC-4), so match the duty cycle to your load type.
Main and auxiliary circuits use screw-type terminals; the main terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid or stranded — or 2x 12 AWG for the US market. The auxiliary switch extension is supported if you need feedback contacts.