This pair of front end caps is designed to fit Centerlock E-sync hubs when used with 15mm axles. The included end caps are also compatible with Neo and Neo Ultimate hubs. The end caps feature a low-friction U-cup seal that snaps into place and stays secure even when your wheel is removed from your bike. These end caps are compatible with both Boost 110mm and older 100mm axle spacing. Fits Centerlock E-sync, Neo, and Neo Ultimate front hubs. Not compatible with 6-bolt E-sync, Neo, or Neo Ultimate 6-bolt hubs. Not compatible with M-pulse hubs.