“(National Pen Products) a prolific pen manufacturer of medium to high grade fountain pens. National pen company used many different names. It has been said if you ordered 100 pens they would put any name you wanted on them. I believe they also bought up other pen companies for their names and/or machinery. They probably made more oversize flattop pens than any other company. In 1934 they owned the trademarks Lincoln, Gold Medal and Gold Crown (and probably more). They probably originated from the CE Barrett company which was at that adress in the 1920's. Gold bond was one of their higher quality pens. Gold medal was possibly sold to Parker or made pens with Parker patents later in the late 30's. The Lincoln pens were earlier than most of the other pens they produced and came in hard rubber. The good service oversize flattops were also made by them.”
Diamond Medal Fountain Pens were sold by Sears Roebuck. In the 1920's and partially into the 30's they were made by National Pen Products of Chicago. They were not offered in any stores except Sears and National Pen Products was not able to sell these pens on their own. They were high quality lever fill pens in the 1920's and the early 1930's. They offered a full range of mens and ladies pens and even combos. They used top grade celluloid, good quality gold filled trim and 14k gold nibs. Since they were made by National Pen Products, you will find similar pens under other names such as Lincoln, Gold Medal and Gold Bond. ( BRUCE WEBSTER in his PENCYCLOPEDIA )
The barrel's imprint : THE JEWELLER , GUARANTEED.