The white "Bunny boot" is an improved version of the Type I "Mickey Mouse boot", designed for use in even more extreme cold weather, and is rated all the way down to . Given the sufferings of the soldiers fighting in the Battle of Chosin Reservoir in Korea, inducing many cases of frostbite, even with Type I boots, the Type II was created to encompass the "worst case scenario" need to field soldiers in the coldest conditions in which any military force could reasonably attempt to conduct operations (including Alaska, Siberia and both Arctic poles). For comparison, the average winter temperature at the South Pole in Antarctica is roughly . The boot is slightly bigger and heavier (~8 oz. (0.22 kg) more per boot) than the black Type I because of the extra insulation. These boots are manufactured by several companies including Bata, Acton and Air Boss.