The Siemens SENTRON 5SM3346-6 is a 4-pole residual current circuit breaker (RCCB) — instantaneous Type A, rated 63 A at 40 °C, tripping at 30 mA residual current. It's built for 400 V AC, 50 Hz networks, with a short-circuit current rating of 10 kA. Type A means it catches pulsating DC faults on top of sinusoidal AC, which covers modern electronics with half-wave rectification.
Mounting position is unrestricted — horizontal, vertical, flat, any orientation works.
Above that, derate linearly: 60.48 A at 50 °C, 57.96 A at 55 °C, 55.44 A at 60 °C, 52.92 A at 65 °C, and 50.4 A at 70 °C. If your panel ambient runs warm — say, 55 °C inside a packed enclosure — you're effectively working with a 58 A device, not 63 A.