Speed Stacks are specially designed high-tech Sport Stacking cups endorsed by the World Sport Stacking Association (WSSA) for competition. Each set comes with its own nifty nylon and mesh bag along with our cool Stacker Training DVD, loaded with instructions, World Championship highlights, Sport Stacking techniques and competitions to help you truly "Stack Fast!". Speed Stacks are the only cups permitted for use in WSSA sanctioned events and each Speed Stacks cup carries the official WSSA approval mark. Speed Stacks, Inc. is the worldwide leader in Sport Stacking (formerly known as Cup Stacking). Sport Stacking is an amazing sport of fitness, agility, concentration and quickness. Thousands of teachers, administrators, and parents along with millions of kids have experienced the benefits of Sport Stacking. Become part of the movement!