20-30 mmHg Thigh High Compression Socks help prevent spider veins, varicose veins, swelling, leg pain, Rest Leg syndrome, post-surgery, travel, standing and sitting for long periods, and overall leg health. Compression therapy works by fighting gravities natural force on your body. Venous disease is mostly hereditary, but can worsen with pregnancy, occupation, diet, weight, and overall health. Graduated compression stockings squeeze tightest at the lowest point (ankle) in your legs, and gradually lessen as the stockings go up the leg. This increases the velocity of blood flow back to your heart by aiding the calf muscle to pump (squeeze) the vein walls to move blood vertically.