SHIMANO OCTALINK MTB Bottom BracketFEATURES - Stiff and lightweight for efficient power transfer Durable spline reinforced construction 8-splined OCTALINK interface increases the strength and rigidity of the entire assembly 26 g lighter weight than BB-ES25 - Quick and precise assembly Good chain line control with chain stabilizerPRODUCT SPECIFICATIONS - MODEL NO BB-ES300 - SERIES SHIMANO ALIVIO T4000 Series - Structure|Standard - Spindle|Hollow pipe - Spindle|OCTALINK - Axle length/shell width (mm)|113|68 (BC1.37) - Axle length/shell width (mm)|113|70 (M36) - Axle length/shell width (mm)|113|73 (BC1.37) - Axle length/shell width (mm)|118|68 (BC1.37) - Axle length/shell width (mm)|118|70 (M36) - Axle length/shell width (mm)|118|73 (BC1.37) - Axle length/shell width (mm)|121|68 (BC1.37) - Axle length/shell width (mm)|121|73 (BC1.37) - Axle length/shell width (mm)|126|68 (BC1.37) - Axle length/shell width (mm)|126|73 (BC1.37)