Lid Construction: The large twist-off lid of this mug is a combination of rugged steel with flexible, food-safe silicone which is 100% safe, non-toxic, tasteless, and BPA-free Multipurpose Container: This camera lens multipurpose container is not only used for drinking hot coffee or cold beverages but can also be used as a money box, pen holder and much more Portable Design: The stainless-steel cup is super easy to take out wherever you go. You can also put it in your case, bag and even your pocket, all while being able to fit in standard size cup holders