EDIT: After I was taken as a commentary rightly point out that there is no aluminum but stainless steel, I take this opportunity to add my review. Whether aluminum or steel, there was a slight metallic taste - for me - yet. This, however, is now gone, apparently after the bottle was often used enough. I've gotten three pieces of which, therefore am and I was fully satisfied. A small disadvantage of rubber, which is by the way not available on all models is, however, be mentioned. In side pockets or extra pockets for bottles you get the rubberized models u. May not be good inside, because the rubber then "blocked". But can be quite liveable. Increased to five stars.