Shimano Ultegra Cassette CS-6600 10S 15-25T

Shimano Ultegra CS-6600 10-Speed Cassettes

- Ultegra CS-6600 cassettes with a 13-16-tooth first-position cog are not compatible with Dura-Ace FH-7800 hub or WH-7800 wheel

- Compatible with all 10- and 9-speed Shimano hubs except for 13-16-tooth first position cog cassettes which are not compatible with DA FH-7800 hubs or WH-7800 wheels