With these BBB Cycling BDP-17 Ceramic RollerBoys 12-speed jockey wheels you can make your SRAM drivetrain run like clockwork again. These 12- and 14-tooth jockey wheels were specially designed for SRAM 12-speed MTB groupsets. The ceramic RollerBoys have a narrow-wide tooth profiling to keep the chain well in place during shifting. The wheels themselves are made from a composite mixture plus 40% fibreglass to make them more durable. Durable and strong composite material The BBB RollerBoys jockey wheels are made of a composite material which contains 40% fibreglass. The fibreglass makes the material very stiff and durable and less prone to wear. Thus, these jockey wheels will keep their optimum grip on the chain for a long time! Ceramic bearings The BBB BDP-17 RollerBoys are equipped with low-friction ceramic bearings. These bearings are extremely smooth and exceptionally durable. They are lubricated with special ceramic light oil for the lowest possible resistance.