The Siemens 5SM3316-0 is a SENTRON 5SM3-series residual current circuit breaker (RCCB) rated 63 A at 230 V AC, with a 30 mA residual trip threshold. Two-pole, instantaneous-trip design — no intentional delay, so it clears a ground fault as fast as the fault current rises. Mounts on DIN rail (REG), 36 mm wide (2.5 width units), 70 mm deep, 90 mm tall. Rated for 50 Hz only, so it's a straight 50 Hz market part; if your site runs 60 Hz, this isn't the one.
Full 63 A rating holds up to 45 °C ambient. Above that, it derates: 60.48 A at 50 °C, 57.96 A at 55 °C, 55.44 A at 60 °C, 52.92 A at 65 °C, 50.4 A at 70 °C. If the panel sits in a hot machine room or near a furnace, size the upstream breaker for the derated current, not the nameplate 63 A.