KYLIN SPORT No Noise Stability Dual AB Wheel Roller Core Abdominal Trainers with Knee Mat For Gym Exercise Fitness Equipment Grey/Black Dual Wheel Design which helps you with balance. Strong sturdy design for gym or home use. Great for abs, core and upper body development. Made of high quality material. The Ab Burner is built so that when you advance the wheel, the movement is fluid and seamless so you get peak performance with low risk of injury.