Shimano bb m980 xtr 6873mm bottom bracket bsa thread genuine shimano hollowtech ii bottom bracket assembly set includes left and right hand cups spacers inner cover and inner o rings light weight seal structure helps to remove vital grams sealed cups keep out dirt and water maintenance free compatible with 68 mm and 73 mm shell durable black anodised finish easy installation use tlfc34 or tlfc24 in conjunction with tlfc36 adaptor tool for installation and removal