Help reduce back pain and pressure. This patent-pending lumbar support uses 31 magnets to create a 360° bio-magnetic field for effective pain management. Far-infrared material retains body heat and helps boost circulation. A built-in back pocket lets you use your own hot or cold gel pack. Adjustable double side pulls. Measure around upper hip: Small (28"-32"), Medium (32.5"-36"), Large (36.5"-40"), XL (40.5"-45"), 2X (45.5"-50").