The material quality is good, but it is not free size. I purchased a pair for my old ailing mother who has a thigh diameter of 21inches and below knee diameter of 17 inches ( measured at 10cm from knee joint, as specified ) . These knee braces do not fit. They are too small not just for my mother, but also for me, with thigh diameter of 17inch and lower knee of 14inches. This knee brace is probably good only for kids or very skinny persons. As it is classified as a medical product, it is not returnable.