The Parker 21 was introduced in 1948 as a cheaper alternative to the Parker 51, which it resembles and was very successful for Parker. The production, in various guises, lasted until 1965. It features the very effective Parker aeromatic filler. There are no imprints on the barrel. It has a "Lustraloy" cap with chrome clip stamped "PARKER    MADE IN U.S.A.", with a glossy black plastic barrel.  The cap is a slip-on type, having a chrome clutch-ring on the barrel.

Like the Parker 51, this pen is fitted with a hooded octanium nib.  It is fine Parker  nib which of course writes most pleasantly.

These pens differ from the Parker 51, for which they are often mistaken, by, amongst other characteristics, having a larger "Octanium" nib..  The cap is similar, but has a different clip. Like the Parker 51, this is also a bit of a "must" for any Parker collection, but again, it is a great writing pen, with many years service left. Overall however, these are still quality pens and super writers, as you may expect.