The Apex Pro Collection is built for high endurance cool and cold weather pursuits requiring a more athletic and agile boot. Offered in two heights/variations, 13 inch and a 16 inch, with the 16 inch boot being insulated for added warmth protection. The Apex Pro 16 inch Insulated features our new and improved Thermal Regulating Fleece. Tr Fleece is a revolutionary open-fiber technology that wicks away moisture 33% better than a standard synthetic fleece. 100% waterproof, 100% Muckproof with a Vibram Arctic Grip A. T. Traction Lug outsole for segment leading grip on variable and icy terrain. Strategically placed rubber overlays provide additional protection along the shin and forefoot without adding unnecessary weight.