HSN Code 0404 refers to "Whey, whether or not concentrated or containing added sugar or other sweetening matter; products consisting of natural milk constituents, whether or not containing added sugar or other sweetening matter, n.e.s." This classification code is essential for identifying dairy products for import/export purposes based on their nature, composition, and intended use. Common products under HSN Code 0404 include whey protein concentrate, sweetened whey powder, and natural milk constituents. Additionally, the GST rate for whey and related dairy products under this code ensures accurate trade compliance.