Wobble Board The New Thera-band Rocker And Wobble Boards Combine An Aggressive Anti-slip Base Design With A Sensory Stimulation Surface To Offer A New Performance Level To Balance Training The Rocker Board Moves Forward And Backward While The Wobble Board Has A Rounded Bottom That Moves In All Directions Both Are Made From Lightweight Molded Plastic Wobble Board: 16 1/8 Diameter