Shimano ultegra 6750 compact 10sp chainsetthe hollowtech ii 10 speed ultegra chainset offers an ideal balance of light weight and stiffness making it the perfect choice for both enthusiast and competitive riders please note bottom bracket is not included features hollowglide hollow outer chainring gives vast improvements in rigidity by virtually removing outer chainring flex and hugely improves shift performance even under high load the chainring teeth have been developed to work in conjun