The FS4 Plantar Fasciitis Socks are the first ever Plantar Fasciitis sock to be internationally patented. Using the same technology as the award winning FS6 Performance Foot Sleeve, these socks are specifically designed to keep you on your feet and pain free. The FDA registered FS4 is incredibly effective at relieving the pain of Plantar Fasciitis, chronic arch and heel pain, Achilles Tendonitis or just swelling in the foot. This first and original Patented Plantar Fasciitis socks feature award-winning Compression Zone Technology in each sleeve. Wearing the FS4 PF socks during runs or sports activities will aid in preventing PF symptom onset and act as an overall foot health and performance aid. With precise targeted compression levels, the FS4 features Compression Zone Technology that is designed for proper foot support and injury prevention. Add to that, soft, moisture-wicking fabric and padding in the right places which creates a technical performance sock that strengthens the foot structure and prevents Plantar Fasciitis, as well as, overuse injuries.