Integrated externally screwed bearing system. Fits Dura Ace, Ultegra, 105 cranks (Compatible with all Hollowtech II cranks). An improved lubrication system and smoother bottom bracket operation are key features of the SM-BBR60 models. The new bottom bracket weighs 17g less than its predecessor (SM-BB6700), weighing approximately 77 grams. The components are specifically designed for competitive use. The sealing system has been improved, and the structural rigidity has been increased. Shimano Ultegra SM-BBR60 BSA features: BSA thread (English) Designed for 68mm BC1.37 bottom bracket shells The set includes 2 bearings (left and right), a connecting sleeve and a TL-FC25 adapter