These custom, Swiss made bearings are double sealed, fully serviceable and removable which give a 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 using 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. Standard 6 colours are available on cups - red, blue, silver, black, gold and gunmetal, with the centre tubes being black on the stainless and gunsmoke on the ceramic. Please Note: The 68/73mm width option is the universal type for both MTB and Road bikes, it is not the Hope Road Specific Series model. For the Road Specific model, choose the "Stainless Steel Road" option. Tech Tip: the 68/73mm width option is the most commonly used size for threaded road and mountain bike bottom bracket shells. The wider 83mm width is mainly seen on "downhill" (ie. long travel) mountain bikes.