The Serenity 2000 Magnetic Elbow Tube contains 18 high grade ceramic magnets combining magnet therapy with light support, Comfortable cotton lining, hand wash and hang dry, For proper fit bend elbow 45° and measure the circumference around the elbow, Medium fits elbow up to 9"", Large fits elbow up to 11, 5"", XLarge fits elbow up to 14"", SKU: SEREN108