Leuchtturm Watermark detector, black plastic dish (303733)

Tray made from black plastic, 75 x 50 mm (3 x 2’’). Place the stamp with the obverse facing down in the tray and sprinkle the reverse with chemically cleaned benzine. The dark background will allow you to see the watermark on the light reverse of the stamp. Please note: Only replace stamps in your album once they are completely dry.