Choices and trends of outdoor mountaineering bags: Outdoor backpacks have always been the focus of outdoor enthusiasts because of their unique features, manufacturing process and material selection. According to the different types of outdoor sports, consumers have put forward higher and higher requirements for the professionalism and functionality of outdoor sports backpacks. Most of the existing outdoor sports backpacks use the modification and composite waterproof treatment methods of applied fabrics, as well as sewing, outer lamination processing, etc., by designing air circulation channels in the body part of the backpack, setting password locks, reflective strips, and alarms. Design buckle pockets and pocket nets on the top, body, bottom and sleeping bags to improve the waterproof, breathable, safety, loadability and other conventional functions of the backpack, as well as health care, adjustable carrying, and balance center of gravity and other new functions. Of course, with the development of science and technology, the expansion of users, and the in-depth exploration of user needs, sports backpacks have also developed more distinctive design forms Backpacks are divided into two categories: one is a large backpack with a volume of 50--80 liters; the other is a small backpack with a volume of 20--35 liters, also known as "assault bag". Large mountaineering bags are mainly used to transport mountaineering materials in mountaineering, while small mountaineering bags are generally used for high-altitude climbing or assault peaks. Mountaineering backpacks are designed to cope with extreme environments. They are exquisitely made and unique. Generally, the body is slender and long, and the back of the bag is designed according to the natural curve of the human body, so that the body of the bag is close to the back of the person, so as to reduce the pressure on the shoulders by the straps. These bags are all waterproof and won't leak even in heavy rain