Zylex®, 2F Easy removal for washing &, drying Comfort rated to -75°, C/-60°, F This 4-layer version of our Zylex liner offers all the benefits of the traditional liner, but with an extra layer of protection. So feet can stay warm & dry in extreme temperatures. & like all our liners, these are easy to remove for quick overnight drying. Ice Lock&trade, Ice Lock&trade, is a patent pending technology that dramatically increases traction on snow & ice. Micro-glass filaments are aligned in the rubber to help create surface tension, so feet can stay firmly planted on the ground no matter what the weather.