My 11 year old and I did a little experiment with this bottle, we put ice in it and left it untouched with just the lid on it for 24 hours to see how long ice could last. We checked the progress at 12 hours and again a little over 24 hours later and there was still ice left - check the pictures! I’m very impressed with this little bottle, and I love that it comes with a straw and a bottle brush. I’m not normally a big fan of red colored item person, but I really love this bottle. It is now one of our go to bottles, and stays colder long than my other name brand bottles.