The 5GJ7 (also designated ECF801) is a 9-pin miniature compound tube containing a high-mu triode and a frame-grid sharp-cutoff pentode in a single envelope. Designed for high-frequency applications including VHF oscillator-mixer, sound IF, and video amplifier service in television receivers and radio front-ends, it operates on a 4.7V/600mA series heater with controlled warm-up time. It was utilized in series-string chassis designs by manufacturers such as RCA Victor, Zenith, Philco, and Sylvania. Available in NOS and tested used conditions.