The shimano xtr m9000 race hydraulic disc brake single has an overall lighter weight thanks to carbon lever blades and magnesium master cylinder it also features further improved thermal management which has been increased by 10 percent with insulated pistons and pad coatings the new i spec ii mounting has a narrow clamping band which frees up more space and gives a cleaner look to your handlebar available in either front right hand side or rear left hand side