A safe and versatile Core Training tool, that helps develop core muscle groups while improving posture and balance. Highly versatile - use standing, sitting, kneeling, laying down and in tandem with exercise equipment such as balls, resistance cables or two Balance Trainers at a time. Enhances core muscle development and strength by isolating specific muscle groups. Two sided for different training surfaces. 13 inches in diameter 3 inches in height. Made of soft, pliable polymer. Can be wiped down after use.