Dynafit X4 Speed Sock
Where to Buy
Here's what other sites are saying:
The same ridge you skin up in the winter becomes the venue for your summer runs when you slip on the Dynafit X4 Speed MTN Sock and let your feet do all the work. Between your foot and your trail running shoe, this ultralight sock provides the dynamic interface to keep your foot dry and ever-prepared for the next stride on the loose scree trail.