Front 9mm QR SealLock end caps for Neo OS and Neo Ultimate OS hubs. Allows conversion of 20mm through axle hubs to 9mm for use with Quick-Release (QR) skewers. SealLock 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. Fits both 100mm and Boost 110 Neo OS hubs. Not compatible with non-OS hubs or Centerlock hubs.