Check before you buy.
I bought 2 of these, as my kids were going on a Scout camp the following weekend. Design and function appear good, but.... After purchase, I was having trouble peeling off the labels on the mug sides, and so I soaked them in warm water and detergent. After washing, I noticed that one of the mugs had a sound of water trapped inside the insulating gap between the inner and outer. The base surface of the plastic inner had a big crack across it. Not sure how it would have happened in transit or on shelf display, but it was beyond use.