HTS code 9902.13.51 covers "Socks with uppers comprising neoprene measuring 2.5 mm in thickness and covered on both sides with jersey knitted fabric of nylon; such socks with underfoots of breathable neoprene measuring 2.5 to 3 mm in thickness and covered on both sides with a jersey knitted fabric of nylon; the foregoing each formed anatomically so as to be designed for the wearer's left or right foot (provided for in subheading 6115.96.90) " 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.