The 3RT1024-3AP08-1MA2: A 3-pole power contactor from the Siemens SIRIUS family, size S0 frame, built for switching three-phase motor loads and resistive loads in industrial control panels. Rated for AC-4 duty at 12.5 A at 400 V, which means it handles the tough reversing and inching cycles that eat standard contactors for breakfast. Motor ratings go to 7.5 kW at both 500 V and 690 V, so it covers 400 V class and 690 V mining or marine installations. Three normally-open main contacts, no normally-closed on the mains — that's the usual arrangement for a line starter where you're switching the motor leads.
Width is 45 mm — that's a single 45 mm module on the DIN rail, leaving room for overload relays and auxiliary contact blocks in the same row. Depth at 140 mm means it clears most standard enclosure backplates, but check your gland-plate clearance if you're shoehorning into a shallow box. Screw-type terminals on the main circuit accept up to 2x 10 mm² stranded, or 2x (16–12) AWG. The control circuit terminals are sized for 2x (0.25–2.5 mm²) solid. That's enough for a 10–12 AWG motor feed in most industrial panels.