Because backpacks are used in special environments, higher requirements are put forward for the materials and processes of backpacks. All backpack force positions are sewn three times with stitches back to the needle, making the force position rugged and durable. Backpack clasps and other parts can be made to freeze, anti-smash and 120 degrees Celsius deformation is not damaged. The exterior of the backpack is mainly 420D Oxford nylon, 1000D nylon, 600D or 1000Dpolyester (polyester), or 1000D Cordura and other materials. 1000D material density is high, very wear-resistant, very suitable for use in the wild. Cordura is a very famous high-grade wear-resistant nylon roving fabric developed by DuPont Company in the United States. The material is much more wear-resistant than the average nylon or polyester, and is lightweight. More than 90% of the world's famous brands of backpacks use this prestigious nylon material. These materials can withstand the water pressure of the 0.5m~2m, so that the objects in the package remain dry. Some materials also have a tear-proof function, once punctured, the break will not rip open and expand.