The labeling process entails stamping, writing, or printing a name, symbol, or number, often in a specific color, on the bag containing the drugs. The bag may be sealed with colored tape, which in itself can serve as an identifier. This article contains a list of about 400 separate heroin labels, gathered through nearly 2,000 observations or reported instances of heroin labeling. Heroin labels often indicate the potency of that particular sample. The potency of street heroin may depend on dealer discretion or geographical area. Heroin users use various techniques to ensure that they buy good quality drugs: using a regular dealer, hearing news through the street grapevine, or going by brand name. Not all heroin being sold in New York City is labeled; the practice originated in Central and West Harlem, and has spread throughout Manhattan and the other boroughs. 4 notes