DNP is on the part. Barcodes applied onto thousands of parts used in an automobile are printed with extremely durable DNP TTR that can withstand the high solvent, heat and abrasive conditions of automotive manufacturing plants. DNP is under the hood. Gasoline, engine oil, and transmission fluid are just some of the harsh chemicals that can be found underhood. Our ribbon produces barcodes that are chemical resistant and hold up to tough working conditions.