Plantar Fasciitis Socks Quarter Crew Size:XL The thoughtfully engineered base includes The thoughtfully engineered base includes a no slip rubber grip bottom that keeps it stable during use The splint creates a dynamic springboard action under the big toe joint or first metatarsal using the tension band concept to distribute force across the length of the entire metatarsal instead of directly on the joint during the toe off segment of walking or running (propulsion) The Plantar Fasciitis Sock features Compression Zone Technology® using four zones of light to firm compression (20 30mmHg) to heel and arch pain The zones stretch the plantar fascia