These are miniature light bulbs, round in shape, with signal colors of red and blue. They were at my parents' house. They are believed to have been used in science classes in elementary schools from the Showa to Heisei eras. Red: 2.5V Blue (Green): 2.5V I have confirmed that they light up. Would you like them for experiments or crafts? Please purchase if you understand that these are used items and have been stored at home for a long time. Returns are not accepted.