Boasting a four arm design for reduced weight and optimum stiffness the shimano ultegra fc 6800 bicycle chainset 11 speed features a hollowtech ii design with a hollowglide outer chainring to improve shift performance even under a high load it also has chainring teeth that have been developed to work in conjunction with 11 speed hg ev chains for greater efficiency and better power transfer lm features shimano ultegra fc 6800 bicycle chainset 11 speed four arm design reduces we