The Arcteryx Fission SL Jacket has an outstanding warmth-to-weight ratio, & has been made using GORE-TEX Pro Shell protection & Arcteryxs exclusive laminated Therma Tek non-quilted insulation. The Fission SL is the lightest fully waterproof insulated jacket in the Arcteryx winter line. Features Fabrics: N40p-X GORE-TEX Pro 2L/ Therma Tek Waterproof & breathable Athletic fit Hip length Insulated, helmet-compatible Stow Hood Fitted collar 2 hand pockets with zippers 2 internal mesh pockets Reinforced fabric on all high-wear areas Pit zippers aid ventilation WEIGHT: 614g Glossary GORE-TEX Pro Provides the highest level of durable waterproof/breathable performance available. GORE Micro Grid Woven Backer delivers garments that are consistently the lightest & most compact in the industry. GORE-TEX Pro has a sparsely woven nylon backer that is twice as durable as traditional tricot liners & allows moisture vapour to pass quickly through to the GORE-TEX membrane. N40p-X GORE-TEX Pro 2LA tightly constructed plain weave nylon face with false twist textured warp & fill yarns, & a micro-grid woven backer. It is lightweight, durable & water repellent thanks to its DWR finish. Therma Tek A DWR saturated, hollow-core, continuous filament fibre insulation that is boned to a DWR-treated 30D high tenacity face fabric. Highly water resistant, exceptionally warm & compressible, but wont lose its loft. DWRA finish applied to a fabric that will bead-up water on its surface to stop it soaking into the fibres. This maintains breathability & shortens drying times.