The Medical Compression Stockings (D.V.T. Stocking Thigh High – Pair) provide graduated compression. The compression is strongest at the ankle and gradually decreases. Any abnormal backflow of blood is effectively stopped by this controlled and graduated compression. Their purpose is to strengthen superficial veins, preventing varicose veins. With high-quality, stretchy nylon and spandex yarn, these seamless stockings are woven on state-of-the-art circular looms. They are tapered from top to bottom. The spirally woven elastic thread allows uniform compression even on unevenly sized limbs. You will find these excellent features make this product a smart choice. Measure circumference around calf approximately 6 inches below knee.