1. Combine three kinds of lightening materials, comfortable carrying system, breathable and strong. 2. Wear-resistant nylon fabric, comfortable and thick shockproof shoulder strap. 3. The ergonomic carrying system design is more labor-saving and more breathable. 4. The top small pocket can be placed in a mobile phone and other items for easy access; the side has a USB jack; the back buckle has a whistle.