The 6C8G is an octal-base high-mu twin triode introduced in the late 1930s for voltage amplifier, phase inverter, and mixer service in broadcast radio receivers and early audio equipment. Featuring a shoulder-type ST glass envelope and two top-mounted control grid caps, it offers high voltage gain while maintaining grid-to-plate isolation. Electrically, each section performs similarly to a single high-mu triode stage, serving as an early octal precursor to later dual triodes like the 6SL7GT. Operates on a 6.3V heater and fits standard 8-pin octal sockets. Available NOS and tested used.