Used Cannondale Lefty Ocho 100mm for 27.5" wheel. Came off a 2018 Scalpel size small.
Works good, holds air, no oil leaks. Raced by a kid in the Colorado highschool league for a few seasons, and includes the sticker to prove it!
Lots of scuffs and scratches, some wear from the brake hose rubbing. One significant scratch on the stanchion. No air or oil leaks. Feels nice and smooth.
Includes brake mount for 180mm front rotor. Missing the pinch clamp that holds the brake hose to the stanchion guard, but a zip tie works just fine at this location to hold it.