The Siemens 3RT2027-2AB04 is a SIRIUS power contactor in Size S0, rated for 27 A at 480 V AC-3 — that's the motor-switching duty class, so it handles full-load current of a motor up to that rating without welding the contacts on break. The 45 mm width and 102 x 144 mm (H x D) footprint fit standard 35 mm DIN rail per DIN EN 60715, with screw and snap-on fastening. Spring-type terminals on the magnet coil and main contacts accept solid or stranded wire from 1 to 10 mm², and up to 2x (0.5... 2.5 mm²) for the coil terminals — no screwdriver needed for the coil connection, which speeds up panel wiring.
The headline 27 A at 480 V is the AC-3 rating — the most common motor-duty curve. That means this contactor can make and break a squirrel-cage motor at full load, up to 27 A, without excessive contact wear.