These glasses do a great job at keeping things cold...HOWEVER...of the 20 that I have purchased, I only have 5 left due to their fragile nature. They are very thin and break so easily that even putting ice into them the wrong way can break the glass. I've had some crack for no apparent reason while they were filled with iced tea and sitting on a counter waiting to be picked up! For that reason alone, I wouldn't buy them again.