I've been using this, http://www.hydroflask.com/products/h...er-bottle-18oz and the narrow mouth version for over two years. I only had to replace the wide mouth cap because the sip-lid thing somehow broke off when I threw it in the back of car. It was time for a new one. Although it still didn't leak after a year and a half of daily commuting use, I did have to make sure it was twisted on tight. It fits perfectly in a bottle cage, but you'll want to make sure the cage is tight or has rubber to grip the metal of the flask. As far as it's primary job it is the best I've ever used. Hot stays hot for a good 5 hours, ice cubes and water even longer. The outside temps don't seem to matter much because I've commuted in the 20's and still the same nice and hot coffee at work. Cheers