Features: Made from nylon material, it is waterproof and wear-proof for outdoor activities and lightweight to wear. Large capacity fits for a 2L water bladder and a separate compartment with multiple pockets for carrying phone, keys, folded umbrella, etc. Extra mesh bag in bottom zip pocket is designed to fasten helmet. Adjustable shoulder straps, chest strap and waist strap fit your body and help to keep the backpack steady. Whistle and reflective trims design make it safer for cycling, running, hiking, camping at night.