The Parker 51 Aerometric was introduced in 1948, this pen was made, in England, in 1955. 

The pen, in Navy Grey, is in first class, near mint condition throughout.  The barrel and hood have a 'showroom' finish with a deep shine and the ding free 'Lustralloy' has retained much of the original frosted surface which was quite fragile and wore away quite quickly with use.  The chromed 'arrow' clip is excellent and is secured with a brass bush and a  pearl cap stud. 

The barrel imprint on the Parker 51 is situated just beneath the cap lip so wears quickly and is very often illegible or totally worn away.  This imprint is quite clear : 'Made in England. 5.'.  The '5.' indicates that the pen was made in the third quarter of 1955.

Navy Grey is one of the less common 51 colours, at the time black was the most popular, perhaps a legacy from the time when virtually all pens were black.  Navy Grey is, arguably, the only 51 colour that looks better with a Lustralloy 'Classic' cap than the 'Custom' rolled gold version.

Although the pen was in superb condition when it came to me I still gave it a good service and check.  The Parker 51 owes some of it's famed writing ability to the 'ink governor' arrangement beneath the hood which acts as a second ink reservoir ensuring good ink flow.  This consists of a number of fine 'fins' which can become blocked with old ink so a through service is always recommended if the pen has been out of use for some time. 

the 'Aerometric', press bar filler system is  easy to use and works well, instructions are printed on the filler sleeve.  The nib is 14Ct, Gold, it is a fabulous writer, delivering a  a super smooth medium line with no pressure. 

The 51 box is the original, it came with the pen and is in fair to good condition.

The Parker 51 has been described as 'the best pen Parker ever made' and this example certainly supports that claim, it would make a first class, and prestigious, daily writer.