The Shimano Road Press Fit Bottom Bracket With Inner Cover, For 86.5 Mm is a complete press-fit bottom bracket assembly for Shimano HollowTech II road cranks the cups are made from fibre reinforced polymer material which reduces the risk of frame noise and damage. This bottom bracket cover set includes left and right hand cups, inner cover, and inner O-rings, the sealed cups keep out dirt and water and this product is maintenance free and compatible with 86.5 mm shells with a 41 mm cup diameter and easy press-fit installation. Shimano Road Press Fit Bottom Bracket With Inner Cover, For 86.5 Mm Features 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 "