This is a Parker 51 stainless steel flighter ballpoint pen from the late 1960's or early 70s. This is a Presentation Pen and is engraved on the shaft with the words "Exceptional Duty" and "6175th ABG" on the other side. The 6175th Air Base Group (ABG) Saw service in South Korea during the Cold War until the very early 1970's.
The pen it's self is in very nice condition with flowing blue ink. The action of the cap is smooth. The shaft shows no wear marks from the cap. Please see photos.