I usually use smaller sizes, and I haven't used the 500ml ones very often, so they've been stored for a long time. One is a Thermos, and the other is either Topvalu or something similar; I'm not sure because they were gifts. Both are in good working order. They have been lightly cleaned, but there are scratches on the bottom, etc., and they are not as light, small, or dishwasher-safe as more recent models. Please be aware of this. I am also selling a smaller set. I think they can be used for things like ice, outdoor activities, in the car, or for pet water.