Bunny boots
Bunny boots or Mickey Mouse boots (depending on the version) are the most common nicknames for the Extreme Cold Vapor Barrier Boots (Types I and II) used by the United States Armed Forces. These large, bulbous, waterproof rubber boots can be worn in extremely cold weather, −20 to −60 °F (−29 to −51 °C), with the liner-free interior retaining warmth by sandwiching up to one inch of wool and felt insulation between two vacuum-tight layers of rubber; this vacuum layer insulates the wearer's feet similar to a vacuum flask.