Sport stacking was invented in the early 1980's in southern California and became an over night sensation in 1990 on a segment of the "Tonight Show" with Johnny Carson.Since then, enthusiasts from far and wide have taken up the sport and have touted its many advantages.It has been proven to help hand-eye coordination and quickness, and train the brain for sports and other activities that require use of both hands.Are you up for the challenge.Hone your stacking skills today! Each cup measures 8.9cm diameter at the top x 6.4cm diameter at the bottom x 11cm tall.The set comes with a convenient carry bag.By Trademark Innovations.