Safety Lamps/Koehler Aluminum Permissible Top Marking
KOEHLER NATIONAL - Aluminum Koehler safety lamp, marked on top PERMISSIBLE MINERS SAFETY LAMP ISSUED TO KOEHLER MFG. CO. MARLBORO, MASS. U.S.A. APPROVAL NO. 209 with Bureau of Mines seal, 9 in. tall, magnetic lock (The Koehler Manufacturing Company was established in 1912 in Marlborough, MA (this is the official spelling but also spelled Marlboro) by Ernest Koehler.