Shimano xtr m980 10 speed mtb cassette this new thoroughbred kit is starts with shimanos first ever off road two ring race crank which comes in carefully calculated closestep gear combinations to match riders individual style terrain and horsepower with primary drivinggear choices the only factor limiting how fast you can go is how much power you can produce xtr offers mindlessly fast shifting and gives racers fewer excuses for losing and even more ways to win its not for everyone but