Arc'teryx Alpha FL 30 Backpack Burly Double Weave - 46% nylon, 46% polyester, 8% elastane Draw-cord closure ALPHA FL 30 BACKPACK - Ultralight and fast, highly weather resistant, alpine strong, and a sterling example of refined, use specific Arcteryx design, the Alpha FL 30 is for built for climbers. ADVANCED COMPOSITE CONSTRUCTION - Laminated, highly waterproof and light weight. Taped seams, permits custom attachments. ALPHA - Lightweight, minimalist climbing and alpinism products that protect from alpine environments. ALPINISM & CLIMBING - Climbing equipment designed for efficient movement and protection in alpine environments FAST & LIGHT - Minimalist, high performance and light weight, for rapid travel in variable conditions.