Superfeet Trim to Fit-BlackDesigned for slim, tight-fitting or lightweight footwear, Superfeet Trim-To-Fit Black supports flat or sensitive feet that may not be comfortable wearing most orthotic devices. Ideal for all arch types. Featuring AgIONŽ antimicrobial top-cover treatment to help reduce bacteria and help prevent foot odor. Recommended footwear: Lightweight and cleated shoes, mountain biking shoes, golf shoes and all types of casual and dress shoes. Sizing: A= women's shoe 2.5 - 4. B= women's shoe 4.5 - 6. C= men's shoe 5.5 - 7, women's shoe 6.5 - 8. D= men's shoe 7.5 - 9, women's shoe 8.5 - 10. E= men's shoe 9.5 - 11, women's shoe 10.5 - 12. F= men's shoe 11.5 - 13, women's shoe 12.5+. G= men's shoe 13.5 - 15. H= men's shoe 15.5 - 17. J= preschool shoe 11.5 - 13.