From the manufacturer:
Koehler Lighting Products has established a long, accomplished tradition in the design and development of batteries and lamps for mine safety. Founded by German immigrant Ernest F. Koehler in 1912 in Massachusetts, our company manufactured the first naphtha-burning safety lamp ever approved by the U.S. Bureau of Mines for explosive coal mine atmospheres. In 1915, that lamp received a gold medal marking the opening of the Panama Canal—the first of a number of milestones. This was followed by the development and production first electric cap lamp power by the WHEAT lead-acid battery.
Today, Koehler Lighting Products is a Marmon Group/Berkshire Hathaway Company with its home in Hanover Township, Pennsylvania. Our commitment to mine safety is as steadfast now as it was when Ernest Koehler founded the company in 1912. This continuing commitment is why Koehler has remained strong for 100 years, and why we remain the leader in underground lighting and portable power solutions.