These bore reducers are designed for use with universal joints, nickel bellows seals and shaft couplings.
They allow the bore diameter to be adjusted, increasing the range of diameters available.
When fitted to hubs with a stop screw, the reducers act as an annular flange, so no marks are left on the shaft.
Shafts can be removed or repositioned repeatedly without touching the reducers, which remain in the hubs.