Shimano drilled lightweight 10 speed cassette designed for super Narrow 10 Speed HG chains. Dyna-Sys is Shimano's next generation MTB 10-speed drivetrain system. The CS-HG81 10-speed cassette sprockets have a spider arm for 3 low sprockets.

• Dyna-Sys technology
• For super Narrow 10 Speed HG chains
• 10-speed drivetrain system
• For mountain bike
• Spider arm for 3 low sprockets