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. The Speed Stacks Competitor provides what you need to get started in Sport Stacking. Our most popular package, the Competitor, includes a set of specially designed Speed Stacks cups, a stem holder with online instructions, and a Gen 4 StackMat (Timer and Mat). Speed Stacks are specially designed high-tech Sport Stacking cups endorsed by the World Sport Stacking Association (WSSA) for competition. Speed Stacks are the only products approved for use in WSSA sanctioned events and each cup carries the official WSSA seal of approval.