10 speed Super Narrow HyperGlide compatible cassette. Fits 9speed spacing older 9sp freehubs requires spline shim. 6arm aluminum singlecarrier reduces weight increases stiffness. 3 largest cogs mounted to carrier all cogs Nickelplated steel. 12,13,14,15,16,17,19,21,24,27T cogs with steel lockring. 235g 1223 Bright polish nickelplated steel. NOTE 1325, 1425, 1525, and 1627 junior models are not compatible with FHWH7800 10speed DuraAce freehubs.
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