Shimano's Dura-Ace 11-Speed Hollowtech II Crankset has set the benchmark in strength-to-weight ratios, which is why it's proven itself at the highest echelon of competition. Made of cold-forged and CNC-machined aluminum, it has hollow crankarms and a hollow large chainring. Both chainrings also feature teeth perfectly designed to assist up- and down-shifts. Perhaps most unique is the 4-arm design that maximizes strength and rigidity where your pedal stroke is strongest. The result is legendary stiffness for awesome power transfer and precision shifting you'll love.