Speed Stacks Competitor - Zippy Leopard w/ Voxel Glow Mat 12 Zippy Leopard Speed Stacks Cups with Bandana Snap Tops G4 Timer & G4 Voxel Glow Mat Quick Stem with Online Stacking Instructions The only cups endorsed by the World Sport Stacking Association (WSSA) for competition. Winner of a 2018 Family Choice Award! The "Family Choice Awards" recognize the best in children's and parenting products. Now in its 21st year, the "Family Choice Award is one of the most coveted, family friendly consumer award programs in the nation.