One size. Fits most trim to fit. Cushions every step. Keeps feet cool & dry. Ventilated soft foam. Compare to Dr. Scholl's Air-Pillo (This product is not manufactured or distributed by Bayer HealthCare LLC, owner of the registered trademarks Dr. Scholl's and Air-Pillo). Our pharmacists recommend. Will not crowd foot in shoe increases walking comfort stays in place. Your insole size is the same as your shoe size. Quality guaranteed or your money back. Made in USA with US and imports parts.