Vintage porcelain enamel advertising sign. Nervigol, a historical medicinal product marketed as a valuable external treatment. The sign features bold white typography on a rich cobalt blue background and dates to the early to mid-20th century. Calcutta, this sign is a striking example of Indian pharmaceutical advertising from the pre-independence and early post-independence era. Its minimalist design, large format, and industrial enamel finish make it a collector’s favorite among vintage advertising and medical memorabilia enthusiasts. Authentic vintage porcelain enamel advertising sign. Product: Nervigol (external medicinal preparation). Calcutta (marked at bottom). Colors: Deep cobalt blue with white lettering. Text: “Valuable External Treatment for Premature Sexual Impotence”. Material: Porcelain enamel on metal. Size: 30 x 20 inches approx. Mounting holes on corners and center top. Era: Early to Mid-20th century c. Highly collectible medical and pharmaceutical enamel advertising board.