The 1862 RS170a Dr Lean St Louis Missouri Private Die Medicine Revenue Stamp is a rare and valuable collectible item from the United States. This 1 Cent denomination stamp, issued between 1861-1870, features a black color and is mint hinged, making it a desirable piece for collectors interested in medical-themed stamps. With its unique design and historical significance, this stamp from Dr. Lean's private die adds a special touch to any stamp collection focusing on United States revenues.