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Profile: The Parker “21”

(This page revised March 21, 2022)

Reference Info Index | Glossopedia  ]

Parker Advertisement, 1952
This 1952 Parker ad shows the “21” Custom, Deluxe, and Spe­cial in the lower half of the page.

Logo In 1941, the G. S. Parker Pen Company wowed the world with its revolutionary “51”, a pen claimed by Parker to “write dry with wet ink.” To accomplish that feat, Parker not only developed a new ink, but also made major improvements in the design of the pen itself. One of those improvements was an enclosed, or “hooded,” nib. On the eve of the Jet Age, the resulting streamlined shape immediately became immensely popular. Nearly every major pen company, and scores of minor ones, came up with pens that — if not actually gifted with hooded nibs — at least looked the part.

Parker’s own “riposte” to the success of the “51” was to find ways of producing a less costly version, and in the years following World War II several such pens came out of Janesville. The first was the Parker “21”, a mass-market model introduced in 1948 at the then-remarkable price of only $5.00. The “21” was a hit, and it rapidly took over more than 60% of Parker’s market in pens priced at $5.00 or more.

Fountain pen

The standard “21” appeared in two basic versions, designated Mark I and Mark II. Behind the clutch, the two versions are identical; the difference lies in the front end. There are, however, multiple cap versions, and because caps are completely interchangeable between the Mark I and the Mark II, the cap is not a reliable indicator of either the version or the date of manufacture.

The first version, shown above, is the Mark I. It had a Lustraloy cap, shown below, with a ridged clip whose ball is a small sphere welded to the clip’s under surface. All “21” variants have their clips set into the cap and secured with a jewel-less metal boss.

Fountain pen cap

Like the “51”, the Mark I bears a date code as part of the barrel imprint, which runs around the barrel, not along it, at a distance of about " from the clutch ring.

The original nib design of the “21” Mark I (below) is as ordinary as it could be; the nib and feed are pressed into the bore of the threaded connector that holds the pen together and provides a mounting for the filler, and the loose-fitting shell screws onto the connector.

Nib design
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The Mark I turned out to have occasional bouts of drying out and blobbing. In 1951 Parker released a revised version, the Mark II, whose nib and feed are held tightly in the bore of a redesigned shell, now an integral part of the ink delivery system. The feed still fits into the bore of the connector, but it is no longer a press fit.

Fountain pen

The most reliable way to tell whether a “21” is a Mark I or a Mark II is to look at the nib and shell. The Mark I, because its shell is only decorative, has a distinct gap between the shell and the top surface of the nib, while the shell of the Mark II is virtually touching the nib.

Along with the internal change, Parker applied a new clip to the Mark II.

Fountain pen cap

This clip’s boldly original design, created by Nolan Rhodes, features a deep “trough,” a concave ridge that works like a long ramp to allow extremely smooth, trouble-free insertion of the pen into a pocket and removal therefrom. From an engineering standpoint, this may well be the best clip design Parker has ever produced, and it was also far less costly to manufacture than the ridged clip it replaced. The Trough clip reappeared in 1954, on the first version of the Parker Jotter ballpoint pen. The Mark II also lacks a date code.

The “21” also carries an ordinarily shaped steel nib instead of the tubular nib used for the “51”. To market the cheaper nib more effectively, Parker bestowed on it the name “Octanium,” reflecting the eight elements used in the stainless steel of which it was made.

Sporting a clutchless slip cap, the “21” has its clutch built entirely into the clutch ring assembly. Instead of the one-piece clutch ring in the “51”, the clutch in the “21” is made in three pieces: a spring, the clutch ring, and a washer.


The clutch ring does not engage the cap; it’s a structural element only. The spring is a ring-shaped piece of stainless steel, slightly deformed to make a rounded triangle, whose three rounded vertices bear on the inside surface of the cap. To hold the spring in position, the clutch ring has a flange on the side adjacent to the barrel, while the washer is simply flat, as shown here, to buffer the spring from the shell.

As shown above, the open end of the barrel is slightly conical, and the exposed side of the clutch ring is a concave cone to match the barrel. This design, which appeared on the Mark II, centers the barrel better against the clutch than plain flat surfaces would do.

The shell in the illustration is a Mark I shell. The nib and feed are held by the connector, as with an ordinary gripping section, and the shell is purely decorative.

The filler in the “21” is a simplified version of the company’s new Aero-metric filler, which also appeared in 1948. Unlike a true Aero-metric filler, it has no lateral hole in the breather tube adjacent to the feed. It also has the short breather tube that appeared on Vacumatic-filling pens in 1946: the quantity of ink that the pen can ingest is limited by the length of the tube, and when the pen is carried with its nib upward, the top surface of the ink does not reach to the breather tube. This design prevents the pen from disgorging ink when it is taken in an airplane.

The Mark II design was very successful, and no further changes were made to the pen’s internals through 1965, when the “21” was discontinued. By 1952, Parker had augmented the line, creating the “21” Deluxe, with a cap bearing longitudinal lines and a gold-plated ridged clip like that on the original Mark I (illustrated below), and the “21” Custom, with a completely gold-plated cap and ridged clip. The basic “21” became the “21” Special, an obvious nod to the 1950 introduction of the plain-jane “51” Special.

Fountain pen cap

Let’s Soup This Baby Up!

By 1956, the “21” line included a truly enhanced version, the Super “21”. With the same tubular Octanium nib featured on the short-lived “41” and the “51” Special, the Super appeared in all of the standard “21” colors. The image below shows the pronounced visual difference between the nib, feed, and shell of the standard “21” (left) and those of the Super “21” (right).

Fountain pen nibs

The Super “21” was made using a different plastic than was used for the standard model, and—as illustrated above—the shells of some Super “21” pens have shrunk over time and are difficult, if not impossible, to remove without damaging them to preserve the collector within. Note that because the barrel and shell of the Super “21” were identical to those of the “41”, Parker could (and did) use up old stock of “41” parts, and as a result there exist Super “21” pens in exotic colors such as Turquoise and Coral.

The Super “21” also introduced a third clip, foreshadowing the aesthetics of the 45 (to be introduced in 1960). This new clip, still a ridged clip with straight sides, featured an imprint of “feathers” at the shoulder and an arrow point at the ball end.

Fountain pen
Fountain pen cap

The final version of the “21” shows only a slight cosmetic change, in the introduction of a profiled Arrow clip matching the clip design used on the 45 and the T-Ball Jotter:

Fountain pen cap

Parker also produced the Super “21” in a Flighter version (brushed stainless steel barrel and cap) using this clip. With its barrel’s end shaped to a flattish cone mirroring the top of the cap, the Flighter shows the 1960s design influence that also produced the cone-ended barrel on the “51” Mark III:

Fountain pen
Fountain pen

The “21” has an unfortunate flaw, a tendency of the shell or barrel, or both, to crack due to the failure of the inexpensive plastic used to make these parts. The “21” Mark II is especially notorious for this failure because of the tensile stress placed on the shell by the press-fitted nib and feed. But because the “21” was made in very large numbers, it is relatively easy today to find a very good crack-free “21” at an equally attractive price (often in the same general range as for an Esterbrook J). And because of its basically sound design, the pen you find is likely to serve you very reliably


The selection of colors initially offered for the “21” comprised four hues: red, blue, green, and black. The green and blue are lighter than the corresponding Forest Green and Midnight Blue offered on the “51”. Later Parker added a gray to the color range, and clear demonstrators are known to exist.

The following table shows the colors of the “21”. The first four colors are the original set that were released in the U.S.A. in 1948. “41” colors that appeared on the “21” during the 1950s are not included here.

Colors of the “21”
Color Name

Black Black
Red Red
Blue Blue
Green Green
Gray Gray
Brushed Stainless Steel (Flighter) Brushed Stainless Steel (Flighter)

  1. How remarkable the price of the “21” was can be understood by comparing the “21” with the much more cheaply made Parkette, a lever filler introduced at $3.50 in 1950.

The information in this article is as accurate as possible, but you should not take it as absolutely authoritative or complete. If you have additions or corrections to this page, please consider sharing them with us to improve the accuracy of our information.

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