This is a 1 1/4" Evolution headset, that fit many Gary Fisher, Alpinestars, Foes, Proflex, Titan, Mountain Cycles, Cannondale, and other bikes from about 1988 to 1994. This one is of unknown origins and make. It has a unique system including a threaded top nut and slotted/tapered sleeve to grab the steerer, which allows you to remove/install your stem while leaving the headset bearings adjusted. It's a pleasing looking design, with that "overbuilt" look that was common in it's day.
Excellent lightly used shape. Hardly a mark. No wear on bearings/races/cups.
- 1 1/4" ahead/threadless
- Stack height: 66mm
- 210 grams