Wanna save some weight in your cage/bottle combo? Zefal makes an extra large bottle, called the magnum, that holds 28 ounces. I use one of these instead of 2 standard bottles, which hold 16? ounces. This saves the weight of an extra bottle cage, and of course one of these bottles is much lighter than 2 regular bottles. And I only give up 4 ounces of capacity.