USED Campagnolo Chorus Ultra-Drive 10-speed cassette, CSK00-CH1015, circa 2000-2008.  Fits Campagnolo 9/10 speed freehubs.  Four largest cogs paired and pinned to lightweight alloy carriers. Steel cogs, aluminum spacers. The 11, 12, 13, 14, 15, 17, 19, 21, 23  25 range is great for strong riders or use with a compact 50/34 crankset.  The correct cassette lockring included.  Review the photos to ascertain cog wear.