These are the adjustable dumbbells that harness water resistance to tone muscles and burn calories and enable full-body water workouts. The two included dumbbells have funnels and fins that provide resistance as you perform curls, chest flies, or shoulder raises. An additional set of fins (bringing the total to eight) can be attached to the dumbbells to provide greater resistance for building muscles and strength. The included caps trap air inside the dumbbells and seal the funnel, making them buoyant and allowing users to workout on the water surface by running in place or performing scissor kicks to tone legs. The funnel caps can also be used to trap water inside the dumbbells, creating two 8-lb. dumbbells. The dumbbells also attach to each other to form a barbell for performing chest presses or front raises. For use in as little as 4' of water. Each: 18 1/2" L x 13 3/4" W x 6 1/2" D. (3 1/2 lbs.)