The Primato 11 cassette is configured with loose, individual chrome plated steel cogs and alloy spacers, so it is completely serviceable and separate cogs can be replaced. An 11-21 11 cog cassette weighs 254 grams. These cassettes are pre-configured 11/12/13/14/15/17/19/21/23/25/28. Includes alloy lock-ring.