These custom swiss made bearings are double sealed fully serviceable and removable which give much greater life span than stock units the bearings are made as all hope bearings are by ina and have been designed to run directly on the crankset axle without the use of shims or spacers again increasing life and reliability hope use a non contact free running labyrinth seal to protect the bearing externally and the machined aluminium centre tube is sealed internally with o rings the unit