From OOFOS, the OOrginal Plus Recovery Thong Sandals feature:  Proprietary OOfoam™ upper American Podiatric Medical Association (APMA) Approved. Awarded the APMA Seal of Acceptance for promoting good foot health and being of exceptional quality Signature brand detailing on the side Slip on style OOfoam™ technology for impact absorption Impact absorbing OOfoam™ footbed MEGA midsole for added comfort Proprietary OOfoam™ outsole Imported.