Prestacycle UniBlock Cassettes are a single-piece unit exquisitely machined from a solid block of cold-forged Chrome Molybdenum alloy steel, then heat-treated, tumble-finished and electroplated for added durability and low-friction operation. The 2 largest cogs on the 11-40 and 11-42 HG11 cassettes are crafted with one-piece of high quality 7075 aluminum. 2 largest cogs are crafted with one-piece of premium 7075 aluminumRed aluminum locknut included (For HG11 freehub only)Use on HG10 freehub requires Prestacycle HG10 lockring (Sold Separately)Single block design allows Prestacycle to remove more unnecessary material, making cassettes lightweight and easier to cleanShifting ramps and profiled teeth provide smooth and consistent shiftsHoneycomb design allows for maximum material removal while maintaining strengthDesigned to last longer than standard steel cassettesItem SpecificationsCassette Body TypeShimano HG 11/12-Speed RoadCogs11-13-15-17-19-21-24-28-32-36-40ColorSilverDefined ColorSilverDrivetrain Speeds11Range11-40Weight317 Prestacycle UniBlock Cassette Cassettes UPC: 689466931785