The Writing Desk Reference Section: Vintage pen information
Aerometric Duofold size comparison
Parker England introduced the Aerometric filling system in the Duofold range in 1952-3. At first only one size of pen was available which was a development of the equal in size Duofold "AF" of 1948 (Aluminium Filler - a new type of button filler using this space-age material). Between its introduction and approximately 1962 the range was expanded to include the seven models pictured above.
From left-to-right: Lady, Slimfold, Junior, Demi-Duofold, Duofold, Senior, Maxima. The Slimfold pictured here is actually a later model from 1968 with the re-styled cap (the Junior was also available in this style).
All these pens were extremely well made, as one can expect from Parker, and the Aerometric filling system makes them practical everyday users. They were available with a wide range of nibs including oblique and italic.