... tone up abdominal,back,shoulder,chest and arms muscles. Ab Wheel exerciser helps tone upper and lower abdominal muscles, obliques, chest ... sure of the exercise you should do.Molded plastic discsDouble wheel for added stabilitySteel rod with comfortable gripsStrengthens arms, shoulders, abs ... .5*15*15cmColor box size: 30.7*15.8*17cm Fitness Double Wheel Exerciser