The Muck Boots Ladies Black Gray Reign Supreme Winter Boot features equestrian detailing with a stylish heathered knit upper and a heel kick finished off with a simple side buckle. The warm fleece lining makes this a cozy winter must-have. Additional features include 4mm CR Flex-Foam insulation, a tall, slim profile, etc sockliner, an articulated heel, as well as a gripping horizontal tread outsole pattern and DWR water resistant treatment on the fabric. Comfort Range: -20 degrees F to 50 degrees F.