Introducing the Kogel Kolossos Pulley OS - a work of art in performance and design. Upgrade your drivetrain with a ceramic 12-tooth top pulley and 19-tooth bottom pulley on the stiffest, most durable derailleur cage. Experience smoother shifts, increased gravel capabilities, and improved chain retention. Compatible with Dura Ace R9100 and Ultegra R8000 in short or medium cage lengths.

Please note** Installing this oversized derailleur cage typically requires replacing your chain to accommodate the larger pulleys.