What fork inner diameter does this star nut fit?

This expansion plug fits **28.6mm (1-1/8 inch) standard threadless forks**, which is the most common size for road, gravel, and MTB bikes. It is not suitable for tapered forks with a 1.5 inch lower diameter. Insert the plug so the top sits **5-10mm below the fork crown** and tighten the center bolt gradually until secure — do not overtighten carbon forks.