All the results of the simulations and the experimentations indicated that the ceramic ball bearings' performances are very good, especially in the low load and high-speed environment.
Size:11T/13T Structure:steel bearing Material: aluminum alloy 7075 Color: Black, Red, Blue, green, Gold,purple,colorful Weight: about 11g Fit for 4/5/6 MM roller screw axis Apply for most of rear derailleur on the market