11T. Rollerboys equipped with ceramic bearings for extremely smooth gliding and outstanding durability. Special tooth profile designed for fast performance during gear shifting. Lubricated with ceramic light oil for optimal running properties. Includes suitable sleeves for various shifting systems. Compatible with Shimano 9-, 10-, and 11-speed/MegaRange, SRAM X9/X7/X0 ('11), Apex, Rival, Force, and Red (after 2011), as well as Campagnolo 11-speed.