KLG are the initials of Kenelm Lee Guiness. part of the Guiness brewing company. He was a automobile racer who designed and marketed a better spark plug just before WW1. He continued to develop more reliable sparkplugs for RAF aircraft during the war. In 1927 he sold the entire business to business to Smiths. Smiths continued to grow the business and 1960 acquired Lodge spark plugs. KLG spark plugs are not common these days but they continue to be made under license by the Enker company of Bosnia.