This Perfect Fitness Ab Carver Pro will strengthen your core and help you get ripped abs and sculpted arms. The kinetic "engine" uses a carbon steel spring designed to turbocharge your abdominal and arm workouts. It provides resistance as you roll out and assistance when you roll back. The ultra-wide tread on the ab carver pro workout provides maximum stability when carving left, right and center. Ergonomic hand grips are angled to help activate arm and core muscles and to make usage comfortable. The high-density foam knee pad provides support and protection for your knees while in use. The non-bulky design of the Perfect ab carver pro makes it easy for travel, and high-quality construction means it is built to last.