The Aircast Pneumatic armband contains a single pre-inflated air cell that concentrates compression directly on the extensor Muscle, delivering instant Relief that doesn't restrict your movement. The Aircast Pneumatic armband provides immediate Relief for those suffering from acute and chronic injuries affecting the elbow, wrist, forearm, and epicondylitis, which is commonly known as Tennis or golfers elbow. The contoured fit coupled with an air cell and soft foam lining make this Pneumatic armband ideal for all-day use. It's versatile for use during both athletic and occupational activities. Universal fit allows the Aircast Pneumatic armband to be worn on either the left or the right arm. One size fits most.