It is ideal and versatile; used in pulling, gripping, and expanding exercises to strengthen the body and muscles Chest Expander & Hand Gripper 2 in 15 Springs,Removable Spring Stainless carbon spring steel wire Pulling Exerciser Hand Grip Strengthening.Resistance Hand Grip Chest Expander Multifunction. One of the most popular exercises for training chest and body resistance. Moves the upper muscles also like back and abdominal while exercising. Improves the muscles resistance and getting rid of laziness and painBefore using the equipment, please check whether the direction of the same buckle, spring tension is connected with a buckle, not 360 degrees rotation, improper use can cause buckle or spring deformation. So check the buckle and the spring is normally connected.