The shimano xtr m9000 race hydraulic disc brake cailper is a lightweight and powerful easily adaptable post style hydraulic disc brake calliper with cutting edge braking technology it features oversized 22mm glass fibre phenolic pistons optimized for heat insulation lightweight and stiffness the opposed 2 piston design reduces leading effect and optimal pad wear increases braking control features easy to use one way oil bleeding for improved oil routing shim less mounting system and banjo s