4 mm provides comfort and flexibility, along with excellent waterproofing, absorption and heat retention properties; adjusts to your foot shape to resist XpressCool lining pulls moisture away from skin to keep feet cool and dry in warm weather; comfort rated from 40 °F to 95 °F (4 °C to 35 °C) EVA midsole for lightweight support and cushioning; etc Sockliner reduces friction and heat build up Lightweight rubber pod EVA outsole offers excellent traction performance and is resistant to oils, High-grade rubber exterior makes for a 100% waterproof boot; rear pull loops for easy on/off