The Siemens 3RT7027-1AP05 is a size S0 contactor with three normally-open main contacts, rated for AC-3 switching up to 690 V. At 230 V it handles 6 A; at 400 V it handles 3 A; at 690 V it handles 1 A. The 690 V insulation voltage and 6 kV surge resistance mean it's comfortable on 400 V line-fed motor circuits with decent transient margins.
The S0 footprint is 55 mm wide, 85.5 mm tall, 91 mm deep — fits standard panel layouts. IP20 on the front and at the terminals — finger-safe, but not sealed. Keep it inside a cabinet; no washdown exposure.
For type 2 coordination (no weld risk on a short circuit), the recommended backup fuse is a gL/gG 50 A NH 3NA. For type 1 coordination (allow contactor replacement after a fault), go up to 125 A. That's the fuse sizing the designer needs to lock in before the panel gets built. Typical for industrial control panels not in a climate-controlled room.