unho Adjustable Weight Vest Jacket Exercise Fitness Boxing Training for Athletes,Police Training, Runners, Sports Training(Empty) This vest is adjustable with 14 sand bags (back and forth), so you can work your way up to 20kg in increments. This vest is great for military/police training, runners, sports training and anyone else looking to add resistance to their workout. This vest is adopt the newest composite material, with its novel design, beautiful shape, bright colors, safety and comfortable to wear, convenient to use, so this would you best choice. This vest suitable for athletes, police, sports teacher, etc. Note: The weigth of this vest is adjustable ( max weight up to 20KG, the vest is with only empty sandbags, no sand or weight included in the sandbags, you could add the weights by yourself).