The double pull wide back support is a highly recommended back brace on the market. Designed by back experts, this braces aim to provide a wider than normal back support. The design of double pull mechanism means the inner wrap provides the best possible compression for your back, heat retention and comfort. The extra strength elastic strap gives you extra stability and support. It has a unique crisscross elastic strap, which is effective in removing excess gap between the breathable fabric and your lower back to enhance stability. This back support belt is ideal for people with a manual occupation or sport where lifting may be involved. It also facilitates good back posture by preventing a slouched position in the lower back. Sizes are according to belly circumference, which is usually larger than waistline. Please refer to product picture on how to measure. S: belly circumference of 66-75 centimeters (26-29.5 inches). M: belly circumference of 74-89 centimeters (29-35 inches). L: belly circumference of 89-102 centimeters (35-40 inches). XL: belly circumference of 102-114 centimeters (40-44.5 inches). XXL: belly circumference of 114-125 centimeters (44.5-49 inches). XXXL: belly circumference of 125-145 centimeters (49-57 inches). Back height of 25 centimeters (10 inches).