Kolossos is the Greek word for a statue, much larger than the original subject. Seems fitting for an oversized derailleur cage.  Imagine the performance of replacing your stock pulleys with a ceramic 12-tooth top pulley and a 19-tooth bottom pulley built on the stiffest cage on the market.

Besides being designed for World Tour victories, Kolossos gives you reduced friction, improved shifting accuracy, and better chain retention.

Compatibility: This oversized derailleur cage fits Shimano Dura-Ace's RD-R9250 and ULTEGRA RD-R8150 Di2 rear derailleurs. 

** Please note Installing this oversized derailleur cage typically requires replacing your chain to accommodate the larger pulleys.   Full installation instructions can be found here