... Use a tape measure around your chest just under your arm pits to determine the size you need. Size small will fit a size 34 to 36 inch chest. Size medium will fit a size 37-40 inch chest. Size large will fit a size 41-44 inch chest. Size X-Large will fit a size 45-48 inch chest. If the item you are looking at is not your waist size, please click on the link to your correct size located on the left side of this auction in the description area. You can also click on the "Visit seller's store" link listed in this auction for the complete selection.