50L Waterproof Backpack with Airstripes Back System that allows for all-around ventilation. Mesh back panel, shoulder straps, and waist belt to encourage ventilation for a cool and dry hike. Pockets on the waist strap allows for easy access to items you would like without having to remove your backpack. Emergency whistle added to the chest strap for quick access. Added pocket for bladder with a fixed buckle for the straw from the bladder.