Thanks for the prompt reponses. From what I can see for various web based retailers it was impossible to understand why they sell differing lockrings. That has put my mind at rest. Any thoughts on whether you need a Campag C9 chain or not? If not then what would you recommend? Myther bike is a Shimano rquipped MTB and I have just discovered that SRAM chains are often superior to the Shimano equivalent. So I was wondering whether the same applies when matching Campt cassettes to chains.