I purchased a swell bottle last summer thanks to one of my closest friends. We went to the beach and she was drinking out of one so I took a sip and couldn’t believe how cold the water was after being in the hot sun. Another girlfriend of mine at work brings her coffee in her swell bottle. I gave it a try and my coffee was still hot at the end of my work day. I would definitely recommend buying one if you already haven’t. I bought mine at target.com. You can also purchase them on amazon.com.