The Shimano Dura Ace CS-7900 10 Speed Cassette is built to be sturdy and light and give you top of the line performance. To help shed some weight, the Dura Ace CS-7900 features an aluminum carrier and 4 cogs made of titanium. The aluminum carrier also makes the cassette more rigid which allows for an improved transfer of power during pedaling. The Dura Ace CS-7900 fits together perfectly to give you faster and more responsive shifting. The sprocket sizes are 11-12-13-14-15-17-19-21-23-25. This cassette features an 11-25 ratio and includes a lockring and the technical manual.