Vigorport backpack chest strap is made of premium high stretch elastic band and heavy duty quick release buckle. It allows you to adjust the tightness and length of the chest belt as needed. The sternum strap for backpacks is elastic, that can keep the shoulder strap of your backpack securely in place. Two pressing buckles design makes it more convenient to put on and detach. Reflective lines on the chest strap can increase the safety of walking at night or in dark place. The backpack strap adjustable length is 7.8""/20cm-13.7""/35cm, compate with most people.