DS1 molded outsole - outer and inner grip; Removable molded EVA sockliner; Double achilles heel and instep reinforcement for comfort and protection; Nylon shank; 2 inches taller than their regular model for extra protection from the elements, brush and debris; Customize to fit larger calves for optimum comfort and protection; Extra room to accommodate layers of clothing tucked into the boot; 6 layers of protection + EVA cold-blocking midsole = 7 layers; Extra layers of insulating warmth and protection! 5.5 mm bootie; 2.5 mm DENSOPRENE XD foam (extreme density) for extra protection; 2 mm airmesh; 2 mm warm fleece lining