Arc teryx Nuclei products have non locking zippers by design. One purpose of the non locking zipper is that it is easier to operate with one hand. This design feature also helps to limit the possibility of damage to the zipper and lightweight face fabric directly adjacent to the zipper. Leveraging the lightweight performance of CoreloftTM synthetic insulation, AireticaTM ripstop nylon and highly efficient ergonomic patterning, Arc teryx created a hooded alpinist s belay jacket that packs to the size of a water bottle and delivers effective warmth for a mere 285 grams. Articulated patterning and underarm gussets provide elevated ergonomic freedom. The fit is trim for maximum thermal efficiency. Features: Packs up small for easy travel storage Breathable Great warmth to weight ratio Lightweight Low profile Compressible and packable Micro seam allowance 1.6 mm reduces bulk and weight Anatomical shaping for fit and comfort Articulated elbows Gusseted underarms Insulated hood Hood fits under helmet Full front zip with chin guard and wind flap Adjustable hem drawcord Internal stow pocket with attachment point Two hand pockets with hidden zippers Included mini stuff sack with drawcord closure Trim fit, Hip Length Weight: 285 g 10.1 oz Activity: Rock Climbing Ice Climbing Alpine Climbing Hiking Materials: CoreloftTM 80 80 gm insulation. Made with highly crimped multi denier siliconized polyester yarn, this lightweight, breathable, and thermally efficient, 100% polyester staple fibre it is very compressible and has excellent loft retention. CoreloftTM 60 60 gm insulation. Made with highly crimped multi denier siliconized polyester yarn, this lightweight, breathable, and thermally efficient, 100% polyester staple fibre it is very compressible and has excellent loft retention. AireticaTM 100% nylon, 34 gm . Tightly constructed, high tenacity, 20x10 denier ripstop nylon with a smooth hand.