Simms' G4Z Bootfoots bring superior warmth and adept performance to unforgiving forecasts. Pinnacle 3-layer GORE-TEXA(R) PRO SHELL in the upper and 5-layer in the legs, synched with patented front and back leg seam construction, enhanced breathability while maximizing both comfort and mobility. Powered by the most feature-rich mix on the market, G4Zs also include a YKKA(R) waterproof center-front zipper for easy access/optimal ventilation, plush handwarmer pockets. The boot story begins with an ultra-gripy, fully-integrated proprietary design. Rugged triple-layer vulcanized rubber maximizes durability and wading performance in extreme conditions. Insulated 7mm neoprene lining (rated to -40 degrees F.) with grid-fleece moisture management keeps hardworking feet dry, happy, and comfortable. The design includes a 12mm felt outsole that accepts cleats and studs and dual density eva midsole for shock absorption. Additional stability provided by removable Right AngleA(R) Footbeds that optimize underfoot ride.