It's an amazing product. I use this in an home gym where the temperature in the room can drop below 20 degrees F. It gets cold. In colder weather it takes the edge off and makes it decent to grab the bar. It milder cold it makes the bar downright toasty.
However it does have a sad design flaw. The zipper. For those of you who enjoy a more aggressive knurling, please make sure you pull the zipper UP when you are zipping. Over time you zip the sleeve across the bar, and it files the zipper down. One day that zipper falls apart and your not able to zip it up anymore.
When that day comes, you need a YKK zipper. Very cheap and easy to find. I managed to repair mine for <$15. But I was really disappointed with the current zipper design. It will most likely break again, but it's a wonderful product that I'll keep using until I can find a better solution.