HSN Code 3819 refers to "Hydraulic brake fluids and other prepared liquids for hydraulic transmission not containing petroleum oil or bituminous mineral oil, or containing 70% petroleum oil or bituminous mineral oil by weight." This classification code is essential for identifying hydraulic fluids and related products for import/export purposes based on their composition and intended use. Common products under HSN Code 3819 include non-petroleum hydraulic brake fluids, synthetic hydraulic fluids, and other specialized hydraulic transmission liquids. Additionally, the GST rate for hydraulic fluids under this code supports accurate trade compliance.