The Excursion Pro Low is 100% waterproof and has a lightweight and flexible 4mm CR flex-foam bootie with four-way stretch nylon. The Excursion Pro Low also features Xpress Cool™Lining,an antimicrobial material that helps to keep your feet cool in warmer weather. It also has a built-in etc® sockliner that reduces friction and heat build-up,an EVA midsole,and a lightweight EVA outsole with rubber pods that provide optimal traction and support. Temperature comfort range: Sub-freezing to 95°F.Additional InfoAnti-Microbial,Waterproof,Outdoor