There are five different sizes in the Support Rite range but this is the Extra Small version. A simple thoracic aid, it helps the user to maintain a comfortable & healthy posture. Made from a light, vapour permeable fabric, it is discreet & unobtrusive when in use. Fits chests of 75 to 80cm (29.5 to 31.5 inches) Should be worn over a t-shirt or vest