(See the 4th image for the size chart) These maternity compression medical stockings are made of premium quality, Grade Microfiber Material, breathable & durable compression fabric made of Nylon , Spandex . True graduated compression of 20 - 30 mmHg. Anti- fatigue, Sweat-Absorbent, Anti-Foul, Anti-Slip, Breathable, Eco-Friendly. The socks will be a tight fit when first worn, it's normal.^ By improving blood flowing & circulation, Maternity Compression Socks may help to prevent the ankle, leg, and foot from swelling, which is usually associated with pregnancy. The thigh high compression stockings also reduce muscle cramping while re-energizing tired legs, suitable for people who often stand or maintain a long posture time.^ They may also help reduce the risk of developing varicose veins, so you can stay looking and feeling good! Body slimming! Stovepipe!^ If conditions permit, we strongly recommended purchasing 2 pairs for the same product to replace them, as this will double its life for each pair. and the best washing time is two days, no more than three days, because a long time wearing will affect the recovery of elastic socks. We Guarantee the Socks Will Last Dozens Of Washes While Maintaining The Same Level Of Muscle Compression Treatment & Effectiveness.^ Buy without any risk! Customer satisfaction is our highest pursuit. If you have any questions or suggestions about our medical stockings, please contact us via Email, and we will do our best to give you a satisfactory answer as soon as possible.