microSHIFT ADVENT X Cassette - 10 Speed 11-48T ED Black Hardened Steel Cogs. Sometimes less is more. With 10-speeds 11-48t range and evenly spaced gear steps the ADVENT X cassette allows riders to shift less often to find the right gear while still having enough range to ride what they want. Fewer cogs also means less weight a wider chain for better mud shedding -- it even fits on standard 10-speed freehub bodies so you dont need to buy new wheels for no reason. In short its everything you want in a high end drivetrain.