ERGOACTIVES Carbon Fiber Insole Specialized for Plantar FasciitisERGOACTIVES Carbon Fiber Insole Specialized for Plantar Fasciitis Universal, Reversible For Either Foot Dr. B Carbon Fiber Insole is a comfort insole that is reversible can be used for either foot. The product was created by an Orthopedic Surgeon with 30+ years of experience using patient feedback as an inspiration to develop an even better version of an insole compared to what exists to this day. Optimal Use Under The Shoe's Existing Insole Dr. B