The PRO Gap Cap Expander Carbon is the brand's lightest top cap and expander, made for riders who are chasing weight from their cockpit. It weighs a claimed 24g, which is 16g less than the previous model, and it's a simple swap that suits any lightweight build.
An alloy expander grips the inside of a carbon steerer, so you can preload the headset without the crush risk of a traditional star nut. A carbon top cap finishes it off. It works with any stem, and it was designed to complete PRO's VIBE Superlight cockpit alongside the VIBE Superlight stem and handlebar. Choose 1 1/8 or 1 1/4 inch to match your steerer.