The X-Plug expander is a practical and lightweight removable accessory which allows the locking of the cap adjusting bolt. The special design allows an extremely wide compatibility with most carbon or aluminum alloy steerers on the market. Compatible with most 1 1/4" carbon steerers like 2020 Scott Addict, Giant, etc. Compatibility range of steerer inner diam.: 24 - 28 mm. 100% made in Italy