The N-left configuration means the neutral conductor connects on the left side of the device, which matters for panel layout consistency.
The 63 A rating covers the main feeder or sub-feed in a distribution board, sized for high-load circuits like electric ranges, large water heaters, or sub-panel feeds. The 30 mA trip threshold is the IEC touch-protection standard — it clears ground faults before they reach a level that can cause ventricular fibrillation. On a 50 Hz system only (not 50/60 Hz dual-rated), so verify frequency compatibility if the installation is on a 60 Hz supply.
The 70 mm depth is a standard RCCB depth — it sits flush with the DIN rail and leaves clearance for wiring gutters in a typical 120 mm deep enclosure. Mounting position is unrestricted, and power can be supplied from top or bottom, which simplifies busbar and cable routing.