I just put this upon Ebay. If you have a Sea & Sea housing and are getting the Canon 10-22mm wide angle zoom lens, this will fit it perfectly.
Sea & Sea 31125 Zoom Gear for Canon 10-22mm lens - eBay (item 180471293800 end time Feb-25-10 17:18:59 PST)
Sea & Sea 31125 Zoom Gear for Canon 10-22mm lens - eBay (item 180471293800 end time Feb-25-10 17:18:59 PST)