I couldn't find the ad I have for them, thought is was Neptune but didn't want to state that without the ad.
I believe originally they came in a large wooden box with many dividers and filled with these inserts. I seen one or two at swap meets over the last 25 years. Many collectors didn't know what they were.

Jack Sim

Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at www.gaspumpbible.com
Air Meter ID book also available