CTA Spark Plug Gap Tool

This is a Spark Plug Gap Tool made by the CTA Manufacturing Corp.
The front is measured in inches, reverse side in millimeters. The numerals along the edge coincide with the thickness of the disc at the given point. The hole is used for adjusting the electrode gap. - Aluminum / circa 1980
** CTA Manufacturing Corp., Carlstadt, NJ, started in 1978 with a few specialty tools and after spending over 25 years setting up worldwide distribution for the biggest names in the business, the founders of CTA decided to take some of their own ideas to market. Originally named "Classic American Tools", the company expanded from manufacturing about 20 Specialty Tools to over 1000 tools under the CTA name today. Factories are located worldwide, manufacturing Specialty Tools to meet the demands of today's technicians. Original CTA logo & Made in the U.S.A., the new ones say "Gapper"™