The MT Xpore bib pants features a durable and stretch 3-layer fabrics that offers excellent weather protection and fits perfectly with the MT Xpore jacket. Its construction mix two types of materials strategically placed where you need it most: a tough textured fabric at the knees and a stretchy fabric to enhance freedom of movement. MT Xpore bib pants features the Xpore nanoporous membrane made of recyclable polyolefin and offer a minimum waterproofness of 25K and a minimum breathability index of 20K. The Xpore nanoporous membrane technology offers targeted breathability for all your most extreme winter expeditions. Its zippered thigh vents provide optimal and targeted thermoregulation. And Teflon EcoElite™'s durable PFC-free water repellent treatment, fully waterproof seams and waterproof YKK® zippers help prevent moisture from penetrating. Finally, that bib pants include our newest technology based on bio-sourced fibers, made from sugar cane waste that is then converted into bio-sourced polyester. In short, MT Xpore bib pants is lightweight, durable, fast drying, environmentally friendly and non-toxic.