I have been using Cuppow for a few weeks now. Cuppow is a BPA free plastic lid that enables the user to turn any wide-mouth mason jar into a handy travel mug for hot or cold beverages. To use Cuppow, simply thread the lid-retaining ring of any wide mouth mason jar over the lid and screw tight to secure.
Before using this product, drinking from a mason jar often required the use of a two-piece lid which was cumbersome to remove for drinking. With this product, I can use my mason jar as a to-go mug in the car, at the coffee shop, or as a handy mug at work.
Why a mason jar? Mason jars are easy to come by, and cheap. Furthermore, they are much easier to clean than traditional plastic travel mugs, which are often too narrow to get in to clean. Mason jars come in a variety of sizes/volumes, and can even be found at most second-hand stores for a good deal.