Zipp Steerer Tube Spacer Set Carbon 4/8/12/30MMFeatures 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. Lightweight and precisely parallel to keep the fork headset cockpit secure and smooth Unidirectional carbon fiber construction (no visible cross weave) with a white Zipp logo to match other