New Shimano XTR / Dura Ace  PressFit Bottom Bracket Shimano SMBB9441A or SMBB9241B bottom bracket Complete press-fit bottom bracket assembly for Shimano HollowTech II road cranks Cups are made from fibre reinforced polymer material which reduces the risk of frame noise and damage Set includes left and right hand cups, inner cover, and inner O-rings Sealed cups keep out dirt and water Maintenance free Compatible with 86.5 mm shells 41 mm cup diameter Easy press-fit installation