These Risers allow you to clamp a stock 7/8" diameter handlebar or you can remove the 7/8" reducers and then clamp an 1-1/8" aluminum "fatbar". If you are thinking of going to a fatbar after you bend your stock set this is the riser to go with. Reducers lock into risers to insure no slippage between components, as well they have serrated teeth in them for maximum gripping power on handlebar.