100% Polyester Perfect fit: The back is ergonomically designed, the bag fits perfectly with the human body, and the bag will not move when riding. Wide webbed belts help reduce shoulder burden Highly tear-resistant material, waterproof in a short time, lightweight, scratch-resistant, breathable and comfortable. A breathable mesh pad is integrated on the back to maximize breathability and heat dissipation, providing you with long-term and safe daily use. Suitable for use: very suitable for hiking, running, camping, mountaineering, traveling, skiing, trail running, fishing, cycling and other outdoor activities Suitable for the crowd: Convenient and simple design: adjustable shoulder straps and waist belts can meet your riding, jogging and running needs. Suitable for men, women and children. . Reasonable storage and design: Design multiple storage locations to facilitate the carrying of various necessities. It has reflective material to ensure safety at night.