Review on Set Of 4 Beasea Stainless Steel Insulated Cups - Stackable, Double Wall Vacuum Insulated, 10 Oz Metal Drinking Glasses For Kids And Adults by Brad Collins

I ultimately returned these as I thought they were a bit heavy for camping (112 g per cup). That said, they are great quality.I tested one with some boiling water. The tapered part of the cup (that stacks into the other cups) gets very hot, too hot to hold. The flat rim is holdable, but still quite warm. However, I returned to check an hour later and the contents were still well above room temperature (cup was holdable by then obviously), so the insulating properties obviously work pretty well compared to a standard cup/mug.