Insulation Explained, part 1: Staying Warm
by Matt Fuller, Dr Matthew Morrissey and Dr Mark Taylor 14/Dec/2012
http://www.ukhillwalking.com/articles/page.php?id=5105
What's better, down or synthetic insulation? What exactly is fill power? How can you avoid hypothermia? How is warm stuff tested, and how best can you care for it?