The Core Wobble Board includes a Core Performance instructional DVD led by Mark Verstegen, a worldwide trainer of pro athletes and creator of the Core Performance® System. Join Mark, as he empowers you with his scientifically-proven exercises, to increase your balance, strength, and functionality, helping you feel better, have more energy and reduce pain for an active lifestyle. Made of premium laminated hardwood, the highly-portable Wobble Board has a durable, slip-resistant surface that"s easy-to-clean. The high-impact polyurethane base is fully adjustable up to 4 inches. Increase the level of difficulty as your ability improves. The higher the board, the greater the difficulty in balance and stability.