The PG 11 30 11 speed cassette from SRAM designed for infinite freedom. The 11 to 42 tooth gives a range of gearing that is fast on flats & climbs efficiently. Using light weight stamped steel sprockets held tighter with stainless steel for a light but strong. The cassette also features X-Glide 2 that improves shifting & chain retention. The cassette has a higher corrosion resistance due to JET technology. Compatible with non-XD driver bodies.