Vacuum Tube 6K4 Military Grade for Tube FM Radio Tuner Model No: 6k4 6K4 is a parathermal oxide cathode remote cut-off pentode with 7 pinsMain application: high frequency or intermediate frequency voltage amplification.Basic data1.Filament voltage: 6.3V current 0.3A2. Screen voltage: 230V current 10mA3.Second gate voltage: 100V current 5.5mA4. Transconductance: 4.4