HTS code 9020.00.40.00 covers "Other breathing appliances and gas masks, excluding protective masks having neither mechanical parts nor replaceable filters; parts and accessories thereof › Underwater breathing devices designed as a complete unit to be carried on the person and not requiring attendants" 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.