It’s time to take “burr” out of your running vocabulary. Stride out in our PhD® Run Cold Weather Mid Crew—one of our warmest and most comfortable running socks. They're made with a ZQ Merino blend and include mesh zones designed to help keep your feet warm during long winter runs. With a run-specific profile and our 4 Degree™ elite fit system, with two elastics for greater stretch and fast recovery, these great-fitting wool socks stay in place at every turn and up every hill.