Let me say first, that I LOVE my 20 & 30oz. Rtic cooler cups! The 10oz are a bit of a dissapointment. They are a great size, but don't do the job the big ones do. I filled one with coffee, and took it to work on a warm day. It stayed hot for about 20 minutes, warm for an hour. In two hours, it was room temp or lower. Styrofoam cups perform better! I have filled it with ice water at night, put it on my nightstand, in the morning, no ice left, it was merely cool water.The 20/30 oz models keep ice See full review