Smartwool has 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 our Indestructawool technology designed for added durability and an Achilles tab designed to help prevent sock slippage. And by adding our brand-new Shred Shield technology to our running socks, the wear and tear from toes is reduced, helping you push toward your finish line and achieve higher mileage.