Cats in the wild keep their claws short by clawing through bark, rocks, and rough surfaces while hunting. Indoor cats lose access to that — which is why their nails overgrow.
The KittyPedi recreates that surface, exactly. Cat claws are keratin. The pads underneath are flesh. 100-grit cat-safe sandpaper sits at one specific abrasion threshold — rough enough to wear keratin, soft enough that the pad feels nothing more than texture.
Each digging stroke removes 0.1 to 0.2 mm of tip. The mechanism never reaches the quick. There is no blade. No lever. No force that travels deeper than the surface of the claw.
It is not a careful trim. It is a geometric impossibility of injury — recreating millions of years of evolved feline behavior.