The image is a blue sign with white text and illustrations. The sign is located in a museum or exhibition space with other artifacts visible in the background. The text on the sign is in Japanese and translates to "First-class cruiser Aoba 20 cm gun barrel". 

On the left side of the sign, there is an illustration of a large battleship, which appears to be a battleship. The ship is shown in black and white and is sailing on the water. On the right side, there are illustrations of the gun barrel, which is a type of gun barrel used by the Japanese navy during World War II.

The sign also includes information about the gun, such as its size, weight, and other specifications.