Isokinetics Inc. Balance Disc - 14" Round - Inflatable Stability Cushion for Therapy, Exercise, Core Training, Seats - Many Colors Made of a special PVC, latex-free material. 14" in diameter by 2.5" high; low nubs on one side, raised bumpy nubs on the other Pre-inflated to a level suitable for most uses, i.e., chair air cushion, wiggle/wobble seat, dance/ballet training, etc. (NO pump included) Provides an unstable surface and sensory feedback, training core muscles to stay balanced. Used in physical therapy to maintain and increase balance skills Popularly used as a therapeutic "wiggle seat" to help calm anxious kids, and as alternative classroom seating Isokinetics Inc. brand is sold ONLY by Isokinetics Inc. Look for the Isokinetics Inc. logo on the center of the disc