They don't make a 42mm shim anymore, though I believe they did use to make one to fit the old Elite stem. So unless they have old stock, Evans may just not have updated the item spec when the new size came in.
Ahhh, I see. Wouldn't be the first time that I've had something from Evans where the description /picture was off!
Ahhh, I see. Wouldn't be the first time that I've had something from Evans where the description /picture was off!