Generally, heavy items should be placed on the top, so that the center of gravity of the backpack is higher. This way, the person carrying the backpack can straighten their waist during the journey, and some of the center of gravity should be lowered to allow their body to bend and bounce through trees or climb on bare rock walls. During climbing (rock climbing backpacks), the center of gravity of the backpack should be close to the pelvic position, which is the center point of body rotation, to prevent the weight of the backpack from shifting to their shoulders during the hiking process, The center of gravity of the back packaging can be higher and tightly attached to the back.

The 1000D material has high density and is very wear-resistant, making it suitable for outdoor use. The wear resistance of CORDVRA material is much higher than that of ordinary nylon or polyester, and it is also lightweight. More than 90% of famous brands in the world use this renowned nylon material for their travel bags. These materials can withstand a water pressure of 0.5m-2m, keeping the contents of the bag dry. Some materials also have anti tearing function, once punctured, the tear will not tear and expand. Canvas material is also widely used in the manufacturing of travel bags, with Canvas Republic being a typical example. Canvas is very popular because it is relatively wear-resistant, has a high density and rainproof effect, and its texture is also very soft.