Hanwag Tudela Winter GTX Boot - Men's Leather Patented ultra-lightweight microporous expanded PTFE (Polytetrafluoroethylene) membrane. Durably waterproof and very breathable. WarmthPlusLayer: An insulating layer added to the insole. For extra insulation at low temperatures A winter sole that provides grip even on black ice. HANWAG IceGrip zones made of a special rubber compound with extremely fine glass particles literally claw into the surface of the ice, rather like sandpaper. High-quality cowhide from the Heinen Tannery in Germany. Tanning is carried out in accordance with strict environmental guidelines and using CO2 neutral energy. StraightFit: Last with asymmetric toe box. Provides more space for the toes (by allowing the big toe to remain in a straight position). Particularly comfortable for users with a wider forefoot.