This 4-way stretch support depends on ceramic far infrared emitting elements, believed to retain body heat to reduce inflammation and pain. It provides support to help promote circulation and counteract swelling. The knit sleeve stretches in all directions, promoting strength and circulation and providing comfortable support for the ankle. Light compression counteracts tissue swelling. Fibers have an anti-bacterial treatment that inhibits bacteria growth. Fits left or right ankle. Measure the ankle above the ankle bone, then select your size from above. Caution: Contains latex.