SKLZ Core Wheels Dynamic Strength & Ab Trainer Develops dynamic core strength. Ability to tone the muscles of the entire midsection at once from a variety of different angles Allows for more push-up variations to target the upper body area Enhance traditional plank and push-up exercises Develop pillar strength (shoulders, torso and hips) through a variety of exercises Wheels on each side move together for safety and ground control Lightweight and portable Includes (2) CORE wheels and a training guide