This Penol No. 8 was made by the Christian Olsen Fabrik in Copenhagen around 1940. It is one of the “Aëro” filler designs, which means that it has an ink sac attached to a section with a transparent body. That transparent portion aligns with a transparent “ink window” in the barrel of the pen. The result is a pen with an ink window, but is not a piston filler.
Many Penols are stamped with a month and year of manufacture, however this one is not. According to the book by Martins and Miloro, the No. 8 was in production from 1935 to 1940, although production may have started as early as 1932 and extended as late as 1942. However, production of the Aëro version of the No. 8 was probably only from 1939 to 1940.
The ink window on this pen is interesting because it is transparent only in about half of its circumference. As can be seen on the top of the pen in the above photo, the other half is obscured by the marbling to match the barrel.
Apart from some light brassing on the clip, the pen is in excellent condition. It has a new ink sac and is ready to use.
Total weight: 18.0 g
Body weight: 10.5 g
Total length (not posted): 120.1 mm
Total length(with cap): 128.7 mm
Barrel max diameter: 13.0 mm
Cap max diameter: 15.1 mm