The 10-51t offering provides 510% of range, making it the most versatile cassette in the XTR family. It is also MICRO SPLINE compatible, and built with steel, titanium, and alloy cogs to optimize weight and durability.The 9-45t offering provides 500% of range, optimizing it for compact drivetrains with limited gear sacrifice. This cassette is still MICRO SPLINE-compatible and built with steel, titanium, and alloy cogs to optimize weight and durability.  Shimano XTR M9200 Groupset ReviewKey Features:510% Range: The widest gear range and most frame compatibility of all XTR cassette options.Compact Drivetrain: When specified with smaller chainrings and the mid-cage XTR rear derailleur, the 9-45t XTR cassette provides a lightweight, ground-clearing option with a no-sacrifice 500% range.Freehub Compatibility: CS-M9200 is compatible with the MICRO SPLINE freehub body standard.Build Materials: The strategic use of steel, titanium, and alloy ensures the CS-M9200 cassette is lightweig