HTS code 9817.64.01 covers "Footwear, other than goods of heading 9021, of a kind for supporting or holding the foot following an illness, operation or injury, provided that such footwear is (1) made to measure and (2) presented singly and not in pairs and designed to fit either foot equally" under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.