There is also a company called Intuition out of Vancouver that makes an almost identical liner at a slightly cheaper price. Comes in two thicknesses, 8 and 10 mm, the 8 being comperable to the thermoflex. I heard that the founder of Intuition invented the Thermoflex for Raichle. Some shop guys say it's better, but I find them both equally good. People love zipfits, though, especially if it's a fairly stiff boot.I'm a flexon+thermoflex convert, personally, and have spares stockpiled.