I bought this to ensure I've got enough fluids to hydrate better.Initially the bite valve was stuck shut but as the Camelbak website suggested if you manipulate it with your fingers a bit you'll split the silicone and it will work as designed, apparently this is a common effect of the molding process and is normal.The bottle looks good and serves up water when expected, as long as you keep it filled ;0)Cleaning is easy too.not cheap but it is solid quality from a good brand.