Had this product for about a year. It does a great job keeping your water from freezing overnight. The coldest I've encountered using this product is a 20F degree low overnight.It keeps the water a little cooler during the day.So what's the problem you ask. Durability and abrasion resistance. I'd only recommend if you'll be using it for biking or casual walks. If your out backpacking etc. plan on it lasting no more than a couple outings.
Not much can be said about this insulator. It helps to prevent your hydration tube from freezing and helps a bit with keeping your water cool. However, the black color isn't the best in the summer. The Bite Valve cover is very useful. No more grit after setting your pack down.It must be a decent product, I just ordered my second one for my other hydration system. Thanks Moosejaw & Platypus!