The Strassburg Sock is designed to hold the plantar fascia in the optimum healing position at night, allowing healing to take place during sleep and times of rest. Effective treatment requires a combination of daytime and night-time treatments. Medically proven relief from plantar fasciitis heel painAverage recovery time 18.5 days 97.8% of patients recovered within 8 weeksCool, comfortable, easy to useOne sock in package Sizing Regular (Up to 20" Calf Circumference)Large (Greater than 20" Calf Circumstance)