Genuine Shimano CS-7900 replacement lockring for Dura-Ace 7900 10 speed cassettes. It is made from light alloy and includes a thin metal washer. It is also compatible with most Shimano 7, 8, 9, and 10 speed cassettes. Select the 11T for use with an 11 tooth cog and 12T for use with a 12 tooth cog Return to Top