A fun and challenging way to improve hand-eye coordination, Speed Stacks have been proven to increase reaction time by up to 30%. Stack and unstack specially designed high-tech cups in sequence. Try to improve time with each attempt or race against others as individuals or in teams. Beneficial for ambidexterity, quickness and concentration. Speed Stacks® are designed for maximum speed as well as safe and easy use. Sets include: Twelve 3-3/4" tall cups, Stacking Stem, and instructions. Also includes a Learn Fob for connecting to videos. Watch video!