In this frame there are matchbooks from Electronics Communication Equipment Co. (l B Porter), Montana Electric Supply, National Pole Treating Co., Maydwell & Hartzel ( this is the company that joined with McLaughlin to form Crystaline products and Maydwell insulators) One of my favorites. Please correct me if I got some of it mixed up. Next is I-T-E corp 2 different, Oliver Iron & Steel Corp, Federal Electric Co. 2 different, McGraw Edison Pa Transformers, Paranite Wire Co, and Corning Glass Center.