Before buying a backpack, you need to measure the correct torso length, especially for small and medium-capacity backpacks with a fixed carrying system, be sure to buy the correct size. Ask someone else to help measure the length from your iliac crest to the C7 vertebra. The iliac crest is the top of the hip bone (not the front protruding "hip bone", the top that can be touched by touching the "hip bone" up), and the C7 vertebra is the bottom of the neck. The easiest way to identify the C7 vertebra is to look down at the ground, the most prominent vertebra in the neck is the C7 vertebra. Measuring your torso length will help you choose the correct pack size, usually different packs come in different sizes for different torso lengths.

Sizes are not uniform for different styles from different brands, so please check the comparison results of each backpack before purchasing. Going to a brick-and-mortar store to try the bag is also a smart decision. Most of the staff are trained in how to measure your body and will recommend the right backpack for you.
Now that the new pack arrives, the first step is to adjust some options that cannot be adjusted while carrying, such as the carrying system, read the instructions to learn how to adjust it properly. Most packs have an adjustable carrying system to fit different torso lengths, especially large capacity packs. First adjust the length of the carrying system to suit your torso length, usually through rails, Velcro or loop systems, please adjust according to the instructions.