Fytto"s compression hosiery products use graduated compression to promote blood circulation and push blood from the lower limb back to the heart. Graduated compression means that the pressure is the highest at the ankle and eases along the leg. Compression hosiery can effectively reduce leg swelling and energize the body throughout the day. For those who stand or sit for long hours on a daily basis, Fytto"s compression socks can help you enhance your body conditions and reduce any discomfort due to blood circulation. Style 1007 Ultra Sheer Knee Highs at 15-20 mmHg with reinforced heel and toe. Ergonomically designed socks have a gradient compression to help driving blood back from feet to heart, and achieve the goal of reducing swollen legs and promote blood flow. Additional thickness added to the heel area to provide extra stability. Specially design elastic band to allow maximum wear time without dropping and skin irritation or leaving marks. Breathable and comfortable, thin like your second skin. Oeko-Tex Standard Certified (an international testing and certification system for textiles) -- harmless and breathable material to provide comfort and allow maximum wear time without skin irritation or allergy. ISO13485 certified . Choose from Black and Nude colors. Suitable for both formal and casual occasions. Material content: 25% Spandex, 75% Nylon. Sizing Guide: Please order by American shoe size: Small (5-6) Medium (6.5- 8.5 ) Large (9 and above)