Resistance bands were added inside the track of our posture flex ab roller to provide assistance when curling. This design allows for better control of the movement, enhances training results, and also reduces stress on the joints, making it more suitable for beginners. Kneeling pads included with each flat Ab Roller provide extra comfort and support. Designed for users who want to take the pressure off their knees during their workout without having to purchase an additional one. A timer is also included as well as a beginner's movement guide. The flat panel design provides more stability than a traditional AB roller.