Frank Green has been making reusable cups since 2013. This is their recyclable polymer cup with an internal ceramic coating. The coating keeps the liquid of your choosing exactly tasting exactly how it should be, plus being ceramic, it'll keep a drink hot for longer than the original Frank Green cup. Most people opt for coffee and tea in their Frank Green, but there’s nothing stopping you from going for a carbonated soft drink or something fruity. Just make sure to wash it out thoroughly before swapping beverages. The cup's 7.5cm diameter means it will slot nicely into your bottle cage for your commute to work.