E. F. Johnson Company Product. Inductor. Material: plastic, metal. Size: 4 3/4" diameter coil x 8 1/4" L. Description: gray Bakelite and copper - "200" series fixed coil inductor. Museum label on frame member: "200-205 - 1938." Metal I.D. plate on end brace: "E.F. Johnson Company, Waseca, Minnesota, U.S.A. 200-205."