The Jesa 688 Steel mini bearing has an exceptionally fine polished bearing track surface and incredibly precise balls. The light weight plastic cages allow for lower rolling resistance. The steel, which is extremely strong, helps the bearing keep its shape when under load. To help reduce drag, Jesa increased the radial clearance providing slightly less 'total contact ball patches'. Made in Switzerland.Bont 688 bearing adapters fit over your 688 mini bearings so that they can fit into 608 wheels. These bearing adapters allow you to use a mini bearing in a wheel that was made for a larger 608 bearing. The benefit of using a mini bearing and an adapter rather than a 608 bearing is that you can create a much lighter set up with better acceleration. This product requires cylinder spaces, not the normal self centering spacers.
Royal Assassin wheels only accept 167 or 688 bearings to save weight. They will not fit 608 bearings.