Motor Master Products distributed a range of more than 90 different spark plug brands during the 1930s and ’40s. To cater to ANY whim, they made and sold a variety of spark plugs, like Blue Crown, Republic, and Acme

Motor Master Products Corporation was incorporated in 1934

product line includes automotive parts and components for use in automobiles, trucks, buses, boats, snowmobiles, agricultural equipment, construction and mining equipment, and for use in small engines such as lawnmowers, chainsaws and pumps. Parts and components marketed by plaintiff include universal joints, bearings, lubrication fittings, driveline and driveshaft parts, spark plugs and filters

https://www.hagerty.com/articles-videos/articles/2019/10/02/my-model-a-used-blue-crowns-plugs-that-powered-indy-champions
https://law.justia.com/cases/federal/district-courts/FSupp/463/232/2141142/