I bought this because of my job. I work on a floodplain forest research and I spend many days in floodplains during the summer. It gets very hot sometimes. I used to have a huge water bottle that just added to the weight of my equipment and made carrying my backpack a pain. My shoulders used to hurt a lot. I decided I needed a hydration pack that would keep my water cool for most part of the day. I know this is for winter, but it works well during the summer. My water stays cool from 5:30am till about 3 to 4pm. I have plenty of water. I love using it and that makes me stay hydrated. The weight of the water is distributed that I don't feel like I am carrying about 2 litres of water in addition to the rest of my load. The only downside is that water that remains in the tube to the mouth piece gets warm. I usually toss that out to get to fresh cool water. I can't wait to try this out in the winter.