Only compatible with NEO OS 6-bolt front hubs which use #6804 bearings (20x32x7mm). Neo OS hubs are less common than standard Neo hubs and were made with larger bearings to allow use of 20mm axles This replacement spacer sleeve for 6-bolt Neo 15x100mm thru-axle and 9mm QR front hubs ensures perfect bearing alignment and keeps the axle centered on the bearing. Must be used with bearings that are compatible. Compatible only with #6804 bearings measuring 20x32x7mm. Not compatible with any Centerlock hub. Not compatible with M-pulse or E-sync hubs.