Shimano dura ace 7900 10 speed road cassette super lightweight 10 speed cassette with a rigid alloy carrier for excellent shifting even under the most demanding gear changes featuring four titanium cogs the new dura ace 7900 cogset has further improved shifting quality by creating a more rigid aluminum carrier unit along with a re engineered tooth profile shimano also successfully reduced the weight of the rear wheel assembly by 10 grams features hyperglide sprockets have a computer designed