OLUOLIN Unisex Foldable Waterproof Hiking Backpack Packable Bag Material: Made of soft and comfortable material. The packable backpack is of 20-35 liters in volume when unfolded. Humanization design: On the principle of human body engineering (Ergonomics) design and air exchange of bearing system,creating the most comfortable experience. Perfect choice for travelling, hiking, trekking, camping, climbing, Riding, and other outdoor activities. Multilayer pockets,can be used to hold cellphone,tablet PC,laptop,A4 magazine,wallet,umbrella,chothes,etc.Side pockets can be used to hold water bottles,etc.