You will receive: four straps and four clasps. Use this method to tighten the belt and adjust the length. Prevent the backpack from loosening and slipping. Adjustable length: the width of the packaging tape is 2.5 cm, the total length is 90 cm, and the adjustable range is 25-70 cm. You can adjust the length as needed. STURDY AND DURABLE MATERIAL The chest strap used to replace the backpack is made of sturdy and durable POM and PP black material. Lightweight and comfortable, it can be put in a bag or taken out of the door at any time. Convenience: The backpack chest strap has a quick release function, easy to open. On both sides of the clasp, you can hang keys, headphones, compass and other small items. The backpack strap can distribute the pressure generated by the backpack on the shoulders and back. Fix the shoulder strap of the backpack firmly in place to prevent the strap from slipping, reducing the swinging of body balance. Widely Used: Especially suitable for children's backpacks, school backpacks, school backpacks and outdoor sports backpacks for adults. For example, put it on a backpack for mountaineering, hiking, camping, jogging, etc.