Double-walled vacuum insulation, won't sweat. 18/8 stainless steel.
You people who carry around a plastic milk jug full of water look silly. And if you reuse that cheap jug, you may even be ingesting obesogens and mucking up your hormones. And you look silly. Did I mention that?
If you really need to be THAT hydrated, at least ditch the plastic jug and grab yourself one of these bad boys. Yeti is known for its premium, almost indestructible line of coolers and now they're getting into the drinkware market.
This big beast will keep your fluids ice cold (or piping hot) for hours. And if you drop a weight plate on it at the gym, it'll probably survive, stand back up, and punch you in the throat for being clumsy. – Chris Shugart