Muscle up with the Perfect Fitness Ab-Carver Pro. This sculpting machine will carve your core and help you get ripped abs and sculpted arms. The kinetic "engine" uses a carbon steel spring to turbocharge your abdominal and arm workouts. It provides resistance as you roll out and assistance when you roll back. The ultra-wide tread provides maximum stability when carving left, right, and center. Ergonomic hand grips are angled to help activate arm and core muscles. The high density foam knee pad provides comfort and protection for your knees. Its durable construction keeps you in shape from season to season.