[Automatic Rebound Design] Our abdomen wheel adopts automatic rebound technology, equipped with a intelligent auxiliary brake system, and a built -in brake device to that the steel rebound is smoother. [2-in-1 Abdomen Exercise and Tablet Supporter] Scientific force, automatically rebound, easy to use. Five layers of non-slip materials are used to achieve non-slip, noise reduction, wear-: non-slip layer, enhanced layer, shock absorption layer, noise reduction layer, and support layer. Ab roller has a double widen wheels design that increases the wheelbase and contact area with the ground, reducing lateral sway and providing stable and safe workouts. [Ergonomic Design] Our abdomen wheel adopts ergonomic design and is equipped with elbow support, which can not only exercise back, shoulders and chest muscles, but also shape abdominal, core muscle groups and trunk lines. Specifications and weight loss effects. Colour:B:Black Material:Plastic+rubber Package Contents: 1 * Ab Roller with Elbow Support Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.