Upgrade your SRAM NX 11-speed cassette with the extra low-end of the Wolf Tooth Components Giant Cog for SRAM NX. This 49-tooth cog is absolutely massive, representing a major increase in low-end for spinning up steep hills and mountains without pooping out halfway up the climb, only for your friends to pass you by. Not only is it compatible with SRAM's PG-1130 cassette from the NX group, but it's also compatible with 11-speed cassettes from SunRace. It works flawlessly with SRAM 11-speed rear derailleurs, as well as Shimano 11-speed rear derailleurs with Wolf Tooth's separately available Wolf Cage.