ISIS is a splined interface bottom bracket/crank design used by Truvativ, FSA, Raceface and other brands. FEATURES: Aluminum cups require TruVativ or compatible installation tool Heat-treated thick-wall chromoly spindle handles the abuse of downhill riding Precision full-complement sealed cartridge bearings M12 crank bolts included (unless noted) SPECS: Spindle Interface Type: ISIS BB Shell Width (mm): 68 , 73 Bottom Bracket Shell I.D.: 1.37 Spindle Length: 128 BB/Frame Interface: English Weight: 406