Key Features:The ultimate in reliable lightweight hubs from the ultimate Shimano MTB groupset, XTR Disc hubs are engineered to perform in the most demanding conditions,Micro Spline freehub has be developed to enable the use of a 10T cassette sprocket, to be used in conjunction with Shimano 12-speed cassettes,Micro Spline freehub body with quick pawl engagement (10 degrees) provides perfect traction and instant power transfer,Ball bearing races are ground with Cubic Boron Nitride tool for high precision, durability and smooth rolling,Wide bearing placement gives excellent lateral rigidity further improving strength and durability,Forged then anodized alloy hub shell for maximum strength and long lasting good looks,The hub uses angular contact bearings designed to cradle the balls giving both radial and lateral support for superior strength and durability in real world riding conditions; they also offer precision bearing adjustment and easy maintenance,Easy to use Center Lock Disc Rotor mount for secure hassle free setup,Weight is kept down by using a hybrid one piece aluminium axle / cone,Double contact seals with internal grease sleeve to keep the elements out and the grease in,For 142 x 12 mm dropouts (SM-AX75 axle not included),Can be used with 12-speed Micro Spline cassette sprockets only,Average weight 231 grams.