Square Taper, ISIS, and Octalink Bottom Brackets
Octalink is splined-axle bottom bracket standard developed by Shimano intended as a replacement of older square-taper axles. As with square-taper bottom brackets, Octalink bottom brackets are choosen according to bottom bracket shell width and axle length.
Shimano BB-ES25 Octalink Bottom Bracket 68x121 mm
Octalink BB-ES25 121-mm taper bottom bracket with BSA thread for 68-mm frame interfaces.
FSA Platinum ISIS bottom bracket 68x113 mm
ISIS bottom bracket, 113 mm length, for a 68 mm shell.
GIGA PIPE TEAM SL BOTTOM BRACKET 113 X 68/68E/73