Anyone heard of MotoMeter sparkplugs? Just found 4 used ones in nice shape, they fit Ford Model A, they are take apart type cad. plated patent date 1928 with a removable tab under top nut for setting gap.
There are so many different makes of plugs for pre-war Fords that spark plug collecting is a hobby itself. Firestone and Goodyear even sold plugs with their name on them. I have some that fit an A head called "Lloyd". If I ever find a set named "John" that fit an A I'll be in business.