2-IN-1 AB ROLLER KIT: Each AB roller kit has 3 wheels with a knee pad. 3 wheels are more stable and durable for body training. Consumers smart as you will definitely know which one you should buy. UPGRADED 3-WHEEL DESIGN FOR STABILITY: Most AB rollers on the market have only one or two wheels. Instead, our upgraded AB roller has 3! More wheels are more stable and durable for you to stably carve left, right and center. It is a multi-way roller kit for training. You can use only one or two wheels. It is up to you! ANTI-SLIP KNEE PROTECTING: Every AB roller kit comes with a knee pad. The knee pad is anti-slip and the comfortable. Knee pad can protect your knees from getting hurt. With silent wheels, you get a safer and more comfortable training experience.