OS1st FS4+ Over The Calf Pickleball Compression Socks were designed with superior FS6 & Compression Zone Technology. Reducing swelling and symptoms of plantar fasciitis and general foot/leg pain, these medical grade socks provide 20-30mmHg compression. Constructed with a micro-fiber nylon material that's treated with silver-ion technology to wick away moisture and eliminate odor, you'll enjoy unmatched comfort with no bulk. The right and left design ensures a perfect fit, while the Y-Gore Heel prevents slipping. Get the support you need—it's time to upgrade your performance wear! Machine wash on cold. Tumble dry on low. No bleach or fabric softener.