Review on Fouriers Headset Expander Steerer 22 25Mm by Michael Skerving

The upper compression wedge under the top cover has teeth that could potentially strip the top of the steerer tube. I'm not a carbon expert but bought it to feel more secure from the compressive forces of my stem on my steerer tube just to get it and worry about something else. If that doesn't bother you, it's long enough to cover the entire compression load on any stem (most OEM compression plugs on bikes aren't long enough and therefore concentrate the stem's compression load around one of the bolts).