Replacement Titanium crank arm,Fixing bolt for Shimano 3450 4500 5600 6600 580. Titanium Hollowtech II Crank Arm Fixing BoltReplacement Titanium crank arm,Fixing bolt for Shimano 3450 4500 5600 6600 580.Materials: Titanium Gr2,Gr5(6Al4V),Aluminum 7075-T6,6061-T6Spec: M15 threadsTreatments: Polished,Anodizing(Blue,Gold,Red,Black)Weight: 6.6g