Upgrade Ab Roller Double Wheel : This Ab roller training has two 3.94 inch thick wheel supports, wider front and rear wheels, and good weighing performance of 220lbs. Elbow support for smooth rolling and better control._x000D_ Automatic Rebound Design : Built-in high elastic mute spring, which helps reset when bouncing back, So it's more convenient and controllable to use, effectively protect muscles from strain during exercise. buvyuotu_x000D_ Multilayer Material Roller Wheel : Five layer materials, including anti slip layer, reinforcement layer, damping layer, mute layer, and noise reduction layer. Good sound insulation effect, no damage to the floor. The detachable handle uses thick foam to achieve comfortable holding, sweat wicking and convenient storage. Includes a 13.4 x 6.7 inch foam pad to protect your knee._x000D_ Snap Design : Convenient assembly, snap fastener for supporting iron rod link, making it more convenient and firm to use, without loosening and falling off like screws.