The ETU320 release provides adjustable thermal-magnetic or electronic protection curves, so you can coordinate downstream breakers without nuisance trips. The 63 A rating holds flat from 40 °C up to 50 °C, then derates linearly to 53.55 A at 70 °C — so in a warm enclosure near the top of the ambient range you still have headroom for a 50 A continuous load.
Panel fit and mounting — what the dimensions mean for your layout
That 105 mm width is the standard 4-module (4 x 27 mm) footprint for SENTRON 3VA breakers in this frame size — it clips onto the DIN rail or mounts directly to a backplate with the supplied screws.
How it compares to a common sibling — 3VA1010-2ED32-0JA0
The 3VA1010-2ED32-0JA0 is a smaller-frame 3VA (100 A frame, typically 3-pole) with a lower interrupting rating and a thermal-magnetic release. The 3VA2163-5HL32-0KH0 uses the larger 3VA2 frame (160 A frame) with an ETU320 electronic trip, giving you adjustable protection curves and higher SCCR — 187 kA vs roughly 65 kA at 240 V for the 3VA1010. If your panel was specified around the 3VA1010-2ED32-0JA0, this 3VA2163 will not drop in without rewiring: the 3VA2 frame is physically larger (105 mm wide vs 70 mm for the 3VA1 frame), and the terminal spacing differs. Stick with the original frame size unless you are redesigning the panel layout.