The 4BC5 is a 7-pin miniature sharp-cutoff pentode designed for RF and IF amplifier service in VHF television tuners and radio receivers. Operating on a 4.5V heater rated at 450mA for series-filament strings, it offers high transconductance and low interelectrode capacitance for high-frequency circuit performance. It was utilized in the RF/IF stages of mid-century TV sets and multi-band receivers from manufacturers like Zenith, RCA Victor, and Admiral. Available in new old stock (NOS) and tested used conditions.