Dumbbells and barbells have no fixed weight. You can adjust a weight suitable for your training according to the weight you can bear. In addition to automatic adjustment of dumbbells, it is generally adjusted according to the size of dumbbell pieces. The weights of dumbbell pieces are usually: 1KG, 1.25KG, 1.5KG, 2KG, 2.5KG, 3.75KG, 5KG, 7.5KG, 10KG, 20k. The weight of barbell bars is usually divided into 40KG and 20KG. If you want to know, go to the gym and browse everything.