This is the hand-held trainer that uses liquid resistance to deliver a high-intensity core workout in just 12 minutes. Developed by renowned fitness trainer Diego Calvo, it is filled with a patented blend of liquids and oils that create optimal resistance when moving the weight up/down and side-to-side that engages over 80% of your muscles. Unlike medicine balls or sandbags that can be awkward to hold, the steering wheel-shaped weight offers a wide or narrow grip for better control and support and faster, more intense movements. Crafted from durable ABS, the lightweight device makes it easy to get in a dynamic full-body workout at home or on the go. A free downloadable app guides users through more than 70 exercises. Made in the U.S. 15" L x 11 3/4" W x 4 1/4" D. (5 lbs.)