Monster Fitness Ab Wheel &ndash; Best Ab Wheel Roller for Abdominal Exercise &ndash; Perfect Exercise for Home, Gym, And Were You Travel &ndash; Color Options &ndash; Comes With Knee Supporter &ndash; No Hassle 1 Year Guarantee Two non-skid wheels for added stability Strengthen and tone abs, shoulder, arms and back Comfortable non-slip Foam grips for stability control Easy assembly #1 Year Guarantee