Wolf Tooth Headset Spacers for Trek Knock Block are machined in the USA out of aircraft grade aluminum.

- Compatible with Trek Knock Block system
- These spacers have unique raised features that key to Knock Block compatible stems (made by Bontrager)
- 1 1/8" top (straight 1 1/8" or 1 1/8" to 1 1/2" taper) steerer tubes only