The Shimano Ultegra CS-6500 9 Speed Cassette is built to the same specifications as Shimano's Dura-Ace line and is a great way to get top of the line performance at a reasonable price. The Ultegra CS-6500 9 Speed Cassette features Shimano's Hyperglide sprockets to give this cassette specifically positioned ramps and tooth profiles to give you faster and more responsive shifting. With its aluminum build, the Ultegra CS-6500 is lightweight and still very rigid. The sprocket sizes are 13-14-15-16-17-19-21-23-25. This cassette features a 13-25 ratio and includes a lockring.