The Sandbell® is a cross between a sandbag, a dumbbell, a barbell, a grip bag, a medicine ball, a slam ball, a stability pod, a gliding disk, and a kettlebell. Made of tough flexible neoprene, the SandBell® is the most versatile and enjoyable functional weight training tool on the market. Even more amazing is that the SandBell® utilizes a patent pending fill mechanism that allows the end user to fill or empty the SandBell® with dry play sand. Imagine how much you will save on shipping! *Fill material not included.