Speed Stacks Set - Cool Blue - Speed Stacks are specially designed high-tech sport stacking cups endorsed by the World Sport Stacking Association (WSSA) for competition. Set comes with its own quick release stem with a link to Online Training loaded with instructions to help you learn to "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. By Speed Stacks.