Stay warm and comfortable in the Arctic Sport Extreme-Conditions Rubber Boots from The Original Muck Boot Company. These aren't your grandfather's rubber boots! With a breathable Airmesh and fleece lining, your feet stay warm and are allowed to breathe so heat-robbing sweat is kept to a minimum. For durability, the boots have a molded rubber outsole with added protection from a wrap-up bumper over the sole. They also have double reinforcements on the instep, heel and Achilles area. The CR flex-foam bootie with four-way stretch nylon, snag-resistant cover is 100% waterproof, buoyant, and flexible enough to fit most calf sizes comfortably. Don't let the "arctic" name fool you, these Muck boots are built to be comfortable in temperature ranges from 60 down to -40.Manufacturer style #: ASP000A. Versatile rubber boots for outdoorsmen Breathable Airmesh lining Stretch-fit topline binding snugs calf to keep warmth in and cold out 2mm thermal foam underlay added to the instep area for additional warmth EVA molded midsole with contoured footbed Reinforced toe Double reinforcements on the instep, heel and Achilles area Comfort range of 60 F to -40 F