A member of the class of perimidines that is 2,2-dimethyl-2,3-dihydro-1H-perimidine carrying a [4-(phenyldiazenyl)naphthalen-1-yl]diazenyl substituent at position 6. A fat-soluble dye predominantly used for demonstrating triglycerides in frozen sections and for staining of protein bound lipids in paraffin sections.