These small tools are very handy when studying a (road) map. Rolling the small wheel over the map, handling this instrument like a pen, will make the hand move over the dial. When you start the hand on top / zero you then select the correct side with the requiered scale / ratio you can read the exact amount of kilometers in real life. Nice black aluminum and bakelite versions of this practical tool. Both made in the Soviet Union around 1960. They are both in good working condition with small signs of normal use and age only. They measures ca. 7 cm or 2 3/4 inches high. Check the video for a vintage desk stuff collection!
