Modeled after the style of weight vests used by professional sports teams to improve performance, this is the adjustable weight vest that allows you to burn more calories while wearing it during yoga, tennis, or other exercise, or during daily activities. Unlike painful ankle weights that unbalance your center of gravity, the vest conforms to your bodys core and has a front-loading pouch closed with a hook-and-loop fastener that contains 10 slots which each hold securely a 1 lb. iron bar for a total of 10 lbs. of resistance (individual bars may be removed easily for a lighter workout). The back of the vest has 10 pouches for additional weights. Made of anti-microbial 400 denier nylon with surged and bound seams and a moisture-wicking lining, the vest will not chafe and secures to your body using a lateral hook-and-loop strap around the waist and two shoulder straps that buckle for a snug fit without restricting your range of motion. (The waist strap also keeps the iron bars compressed so they will not jostle during vigorous workouts.) Includes instruction CD and training guide. One size fits most (up to 42" waist).