The TRS+ Cassette is all about range. Using a unique 3 piece assembly, the TRS+ cassette offers 9 tooth to 44 tooth(11sp) or 42 tooth (10sp) range. The largest two (10sp) or three (11sp) cogs are precision machined from aluminum and locked onto a SRAM XD driver body. The remaining eight steel cogs lock into place with a chain whip. The front cogs are shared on the 10 and 11sp versions and high wear parts are available individually which means replacing worn parts, or upgrading from 10-11sp is possible without buying a whole new cassette.