Hollowtech technology enables extremely light, hollow crank arms manufactured using Shimano's exclusive forging technology for maximum rigidity. The new I-Spec II with its narrow clamp provides a tidy appearance, less weight and more space on the handlebar. One Way BleedingThe One-Way Vent is designed to quickly and easily prevent air from entering the hydraulic system. A high performance chainset from the trekking group, using the most advanced 10-speed Dyna-Sys chainrings.Forged HollowTech II aluminium cranks offer unrivalled strength-to-weight ratio. Lightweight construction with external super smooth bottom bracket bearings for efficient use. HG-X chainring with patented spike pins give smooth and fast gear shifts under load. Item Package Dimensions L x W x H:? 11.65 x 8.11 x 7.8 inches. 11.73 x 8.39 x 8.11 inches. Listing and template services provided by inkFrog.