AliMed SI Belt stabilizes muscles and ligaments of sacroiliac joint. Hook-sensitive, 2"W non-elastic belt with nonslip interior conforms to body contours. Elasticized closure allows non-binding comfort during activity. Specify size, see sizing below. Sizing: Measure circumference at widest point of hips. Small: 26"-32". Medium: 32"-42". Large: 42"-52".