Shoulders Back is an all elastic garment that helps you attain proper equitation in a safe and comfortable manner ShouldersBack gently pulls, aligns and holds your shoulders into the "correct" position, allows complete freedom of movement. ShouldersBack is the only product like it on the market! designed for the equestrian, Shoulders-Back helps you attain proper equitation in a safe and comfortable manner researched and developed by a leading orthopededic supply team. The more you slouch the greater the pull. Measure the circumference of the ribcage just below the chest. Sizes: S - up to 22", M up to 38", L 38" plus.