The XT 10-Speed Cassette uses plated steel cogs for superior durability, but that doesn't mean that it weighs a ton. The largest six cogs are minimal in design and are pinned to two lightweight alloy spiders -- three cogs for each spider. The four smallest cogs go on separately, and the whole batch is secured with a sleek alloy lockring. This cassette is compatible with Shimano's Dyna-Sys 10-Speed shifter and rear derailleur.