63 A, 4-pole residual current protection – what you're getting
This is the ABB 2CSF204101R1630 RCD, a 63 A, 4-pole residual current circuit breaker built for DIN rail mounting. Rated insulation voltage sits at 500 V, so it's sized for three-phase distribution boards where earth leakage protection ties to the neutral. The IP2X front keeps fingers out once it's panel-mounted.