The Siemens SENTRON 5SY7220-8MA is a 2-pole miniature circuit breaker rated 20 A at 400 V AC, with a D tripping characteristic and a breaking capacity of 25 kA per IEC 60947-2. It is a magnetic-only trip unit — no thermal bimetal — so it responds to short-circuit faults only, not overloads. That makes it a fit for applications where upstream overload protection is already provided and you need fast, high-current interruption on the branch.
In a 400 V industrial panel with a high available fault current, that SCCR headroom is what keeps coordination intact. It seals with a lockable cover (sealable: yes) to prevent unauthorized operation. The terminal accepts top and bottom combined conductors, so you can daisy-chain busbars without extra lugs.