Powerstep Original Men"s / Women"s Full Length Insoles, invented by podiatrist Dr. Les Appel, helps relieve heel and arch pain, while preventing foot strain and injury. A full-length, prescription-like, flexible polypropylene arch support is embedded in a double-layer polyethylene cushion casing. The result: control for feet rolling inward (overpronation), which can pull the entire lower body out of alignment. The ideal insole for complete foot support, comfort, and correct posture. Flexible polypropylene embedded in the insole supports the arch, helping to prevent overpronation. Polyethylene foam cushions your steps. Sanitiz fabric cover reduces slippage and heat, helping keep feet drier.