Developed and designed entirely by Ceramic Speed, the oversized pulley wheel (sop) system for Shimano 9000/6700 provides the ultimate optimization of your Bicycle’s drivetrain. This sop system features a set of 17-tooth Aluminium pulley wheels, available in red and Black, housed in a specially designed polyamide (switch pant) and carbon cage. The upper and lower 17-tooth oversized Aluminium pulley wheels come Fitted with either standard or coated Ceramic Speed bearings. The oversized pulley wheel (sop) system is the product of choice by many of the world’s leading cycling teams and triathletes. This specific system is compatible with Altegra 6700/6770/6800/6870 mechanical and Di2 rear Derailleurs and Dura ace 7900/7970/9000/9070 mechanical and Di2 rear Derailleurs.