For nagging lower back pain, choose the Relax Wraps Back Wrap. Unlike other wraps that have to be held in place, or heating pads keeping you attached to the wall, the Back Wrap goes with you to relieve back pain. Discreet fabric-covered Velcro closure. May also be wrapped around the shoulder, or around the entire knee. Medium measures 47" long. Large measures 53" long. Weight: 3 lbs. All Relax Wraps can go in both the microwave and the freezer. 100% Flax. Double-lined for added durability.