FC24 - 24-notch bearing cups - Fits for XTR/DURA-ACEBAS BB - For DUB: 24-notch bearing cups with outside diameter 46 mm (i.e. for DUB BSA BB) FC32 - 16-notch bearing cups - Outside diameter 44 mm - Compatible with BB51, BB5700, BB70, BB80; FSA MegaExo; Hope; GXP; Race Face X-type; PROWHEEL and other BSA BB - Fits 16-notch rotor disc lockrings FC25 - Fits for XT/105/ULTEGRABAS BB Key benefits and compatibility - Broad compatibility across multiple bottom bracket standards and notch configurations, reducing the need for multiple cup kits - Clear specifications for reliable fit: 24-notch (FC24) and 16-notch (FC32) options with defined outside diameters (46 mm for DUB BSA BB and 44 mm for 16-notch BBs) - Model-specific mapping to help you choose the correct cup for your system (FC24 for XTR/DURA-ACEBAS and DUB BSA, FC32 for BB51/BB5700/BB70/BB80 and other BSA BBs, FC25 for XT/105/ULTEGRABAS) Use scenarios - Upgrading a bike with XTR or DURA-ACE bottom brackets that uses a DUB or BSA configuration requires FC24 - Building or converting a frame with DUB BSA BB or other 24-notch systems benefits from FC24 at the 46 mm OD specification - Restoring or maintaining older Shimano and other brand setups (BB51, BB5700, BB70, BB80) or mixed systems that require 16-notch rotor disc lockrings can use FC32 - Replacing cups in XT, 105, or ULTEGRABAS BB setups with FC25 to ensure proper fit and function