Designed in the harsh Alaskan Arctic, the BootGlove provides a protecting layer of insulating neoprene for your ski boots to reduce wind chill and prevent loss of body heat in extreme winter conditions. Overall, the BootGlove retains an average of +20°F/7°C in your boot's toe box, conserving heat loss where it's most important...YOUR FEET!Testing:* In an engineered test at Moose Mountain Ski Resort in Fairbanks, Alaska the following results were recorded:The outside air temperature was -5°F below 0° at the ski lodge. Temperature probes were placed on the shell of the ski boots. A BootGlove was placed over one of the boots in the ski lodge. After skiing 1,300 vertical feet, the exposed boot shell temperature was -5° F, while the boot protected by the BootGlove was +48° F. The shell of the boot protected by the BootGlove was +53° F warmer than the other shell. The test was repeated with identical result.