This chest expander is a multifunction fitness tool that targets and builds different muscle groups of your body. It can be used as: a) Chest expander - to develop upper body i.e. chest, shoulders, upper back, arms and core. b) Hand gripper - to develop hands, fingers and forearms, hand grip. Its adjustable design lets you remove any of the 5 springs to ease the tension to suit your resistance level. Remove any of the springs to reduce the intensity of tension or add them back to increase the tension. The chest expander is made of high quality carbon steel springs and quality ABS material. It is lightweight, portable exercise equipment that can be used in your home, gym or take outdoors to exercise. The springs detach with ease making it easy to store and carry it with you.