Leather Working Group Gold-Rated waterproof nubuck leather; One-piece Vibram Megagrip with Traction Lug and 4mm lugs; Quick-lace metal top hooks; GORE-TEX Invisible Fit footwear fabric with 71% recycled polyester face fabric; Dual-density midsole with 30% sugarcane EVA; PU Sockliner made with 50% bio-renewable Susterra propanediol; 100% Recycled polyester quarter mesh, tongue mesh and lining mesh; Hubble Heel and SwallowTail design; MetaRocker with integrated flex grooves