Thermos TS1319DB4 18-Ounce Guardian Stainless Steel Tumbler (Blue)

I love these cups. They keep my coffee warm for hours. I have not tried icy drinks in them, but I believe it when they claim that drinks will stay cold for up to 14 hours. They are spill proof and not complicated to breakdown to wash.

There are several iterations of the lid design. I originally had one of the earlier versions. It was mostly leak tight. However, coffee heavily stained it and eventually the plastic wore down and broke on the slider. I just got a new cup with a newer version of the lid design. It seems leak tight and easier to clean. It should work better. I would not recommend washing the lid in the dishwasher. I think that increased the degradation of the first lid I had.