1 Waterproof and Roomy . The portable backpack is made of nylon fabric with waterproof coating inside. The sewing thread is covered by waterproof fabric. The package is spacious and load up to 20lb stuff. 2 Lightweight and Convenient. After folding, the bag can be put into a small bag 9x6.3x1.2 inches weighing only 5.15 Ounces, which is extremely lightweight.It's very suitable for outdoor activity. 3 Comfortable and Durable . soft cushion on shoulder straps is comfortable and durable. The two ends of the strap adopt special locking technique. It's not easy to break even though you jump and run. The length of the shoulder straps can be adjusted according to different height 4 Safe. the bag is equipped with two net pockets at each side for water bottle . Both sides have light reflective strips to enhance the safety at night travel. 5 Airport Hero.Avoid overweight baggage charges by simply unfolding it from your luggage and using it as a carry on for your excess baggage.