DESIGN: Reinforced back pad provides stability without losing flexibility Form-fitting, contoured design provides a customized fit Hook-and-loop strap with steel buckle allows for a custom fit and easy adjustments Designed to fit the natural curve of the back SIZING: Small: 25"-29" Medium: 29"-33" Large: 33"-37" X-Large: 37"-42" Height: 7.5" Thickness: 10mm