These 7-pin male Bakelite cable plugs feature the classic small 7-pin (SM7) layout with two larger-diameter pins designated for high-current filament or heater leads alongside five standard signal pins. Available in molded black and brown phenolic Bakelite, these male adapters fit standard 7-pin chassis sockets and feature solder-through pin terminals for custom wiring. Historically manufactured by companies like Hugh H. Eby Company, Cinch-Jones, and Amphenol, these plugs are designed for vintage radio speaker connections, umbilical power cables, test equipment adapters, and custom interconnects.