Zipp Speed Weaponry Headset Spacer Set, UD Carbon (4mm x 2, 8mm x 1, 12mm x1, 30mm x 1)Imprecise spacers can cause your headset to loosen, affecting bike handling and component life. Lightweight and precisely parallel, Zipp carbon headset spacers are precision ground to keep your fork secure through every twist, turn and bump in the road. 1 1 8" diameter in 4 (x2), 8, 12, and 30 mm heights UD carbon fiber finish Product Specifics S. H. I. S. Stem Clamp Diameter: 28. 6 Defined Color: Black Color: Carbon Material: Carbon Today's Stock