Adjustment method of the bag retractable buckle: First, pass the strap from the top of the two loops through the two loops, then go around the bottom loop, pass through the top loop, and come down along the original strap, like this Easy to adjust the tightness of the straps.

Generally speaking, when a backpack is sold, the straps of the backpack are already fastened. You only need to adjust the length slightly when you use it.
The most traditional way to tie the backpack straps is to pass the straps through the two loops, then loop back to the bottom loop, and then pass through the top loop, and then you can come down together in the order of the original straps. This method is the most fleece method, but it is the best for both tightness and firmness. When the backpack was produced, it was also tied in this way.
The question of how to wear the straps of the backpack depends on the individual. If you don’t like this traditional tying method, you can also invent some unique tying methods yourself. Firm and solid, not easy to slip off.