Titled “Swiftwick Takes Cycling Tech Into Hiking Socks,” the article states:
To create a performance hiking sock, the company added Olefin fiber to Merino Wool. Fiber First Moisture Wicking technology, the company says, is based around Olefin, an inherent water repellant fiber without harsh chemical coatings. By adding Olefin to the footbed, Swiftwick moves moisture from the bottom of the foot up to where it can escape as vapor. Merino Wool as you know is a natural fiber that is soft, comfortable and excels at moisture management and thermal regulation.
Read more here.