Shimano m810 saint hollowteach ii bottom bracket this genuine shimano hollowtech ii bottom bracket assembly the length of the screw thread is increased to enable the fitment of chain devices and the set includes left and right hand cups spacers inner cover and inner o rings the light weight seal structure helps to remove vital grams and sealed cups keep out dirt and water making this item maintenance free durable gold anodised finish easy installation compatible with both 6873mm and 83