Smartwool put all of their smarts into these new and improved Women's PhD® Run Ultra Light Micro socks. You won't break your stride, thanks to Indestructawool™ technology designed for added durability and an Achilles tab designed to help prevent sock slippage. And by adding brand-new Shred Shield™ technology to these running socks, the wear and tear from toes is reduced, helping you push toward your finish line and achieve higher mileage.