Compression stockings put graduated pressure on the legs to help increase circulation and venous return. The compression socks and stockings are graduated in compression, which means that the amount of pressure applied by the stocking to your leg at your ankles is the greatest, and then becomes lighter as you move up the leg. Compression stockings usually apply 100% of their strength at the ankle, about 70% of their strength at the calf, and 30% of their strength at the thigh. These strengths and percentages vary depending on the level of compression and manufacturer.
Compression stockings come in different levels of compression (15-20 mmHg, 20-30 mmHg, 30-40 mmHg, etc). The stocking will support your legs more or less depending on the level of compression. The various levels of compression are used for different symptoms and leg health issues.