The Siemens SENTRON 5SY4220-6CC is a 2-pole miniature circuit breaker rated 20 A at 35 °C with a B tripping characteristic and a 10 kA breaking capacity per EN 60898. At 40 °C the breaker derates to 18.8 A, at 50 °C to 17.52 A, and at 55 °C to 16.84 A — so if the panel ambient runs hot, size the load against the derated figure, not the 35 °C nameplate. It's halogen-free and silicon-free, which matters if the panel serves a clean room or semiconductor fab where outgassing can contaminate optics or wafers.
The closest functional peer in the SENTRON family is the 5SY7210-7CC, also a 2-pole MCB but with a C tripping characteristic (5–10× In) and a higher 20 kA breaking capacity. If your panel was specified around the 5SY7210-7CC, the 5SY4220-6CC will drop into the same DIN-rail footprint and same 2 MW width — no rewiring needed — but the B curve trips faster on moderate overloads, and the 10 kA SCCR may not coordinate with a high-fault upstream device. Use the 5SY4220-6CC where the fault level at the panel is confirmed ≤10 kA and the load doesn't produce a significant inrush (no motor starting, no capacitive loads).