The 3CY5 is a 7-pin miniature sharp-cutoff tetrode vacuum tube designed specifically for high-gain RF amplifier service in radio tuners and high-frequency receiver front-ends. Featuring a 3.15V heater rating with a controlled warm-up time for series-filament radio circuits, it incorporates dual control grid leads to minimize input loading and lead inductance at VHF frequencies. Available in new old stock (NOS) and tested used conditions.