The Rolyan Workhard Back Support, models A81831 to A81835, is a heavy duty lumbar support aid designed to act as a preventive measure for persons with low back pain. With double waist strapping, it is constructed to provide both lumbar and adominal support. This brace also features adjustable shoulder straps and is not designed to constrict the user's daily activities. DIMENSIONS: Measure around waist - do not use pant size. Model A81831 - Small is 26 to 30 inches wide; Model A81832 - Medium is 30 to 34 inches wide; Model A81833 - Large is 34 to 38 inches wide; Model A81834 - Extra-Large is 38 to 42 inches wide; Model A81835 - Extra/Extra-Large is 42 to 46 inches wide. The back is 9 inches wide. COLOR: Black.