Weightlifting and fitness exercises as an auxiliary equipment. There are two kinds of fixed weight and adjustable weight. ① fixed weight dumbbell. Cast with cast iron, iron bar in the middle, both ends of the practice of solid ball. ② adjustable dumbbell. Similar to the reduction of the barbell, in the short iron bar at both ends put on a round of varying weights of iron, about 40 to 45 cm, lifting weight or fitness exercises can increase or decrease weight. Regular exercise with dumbbells can enhance the muscle strength of various parts of the body.