Avian compression caps to fit 1-1/8 size headsets, 

The Expander Plug included with our 1-1/8" Standard & Tapered headsets is intended for use with 1-1/8" fork steerer tubes with a 23.2 Inner Diameter. That means if your fork has a steerer tube thicker than 2.7mm, our expander plug won't fit inside it. Fork manufacturers that use thicker steerer tubes than 2.7mm should require a stem lock design, or some other type of internal locking included with their fork.