I received this Core SS Autoseal 24oz tumbler to try and I'm impressed. To test it out, I placed 8 ice cubes in the cup one afternoon and checked 2 hours later. Ice was still in tact, no melting at all. 4 hours later I had the same results. I ended up leaving it overnight (another 8 hours). There was still ice in there, but some had lost its form and others melted. The stainless steel body is quite sturdy as my son dropped it. There were no dings, but the drink lid did open very easily. I greatly appreciate the auto seal feature (I'm guessing that's why the drink lid is so easy to open). The seal release is easy to manage with one hand. Overall i like this product and will more than likely purchase another one in a smaller size in the near future.