The hollow tunnel design is honestly what sold me — the gradual sizing between the sections made the whole thing way less intimidating than I expected. Clean finish on the edges too, no rough spots at all.
Didn't expect the hollow design to make such a difference, but it really does — the open core gives a completely different sensation than my old solid one. The graduated rings let me work up gradually instead of jumping straight in, which made the 5.7cm feel way less intimidating.