Classification- It is a Twin triode. Dome-type bulb of glass, copper ceramic base with eight golden pins.
Application -It intended for use a voltage amplifier or Phase inuerter.
Dimensions -Dimensions, outline diagrams of the tube and bases, and the arrangement of electrode connections to the base terminals are shown in the below drawings.

Nominal operating conditions and parameters
Heater voltage : 6.3V
Heater current : 0.6A
Plate voltage : 250V
Grid voltage : -8V
Plater resistance : 7.7kohms
Plate current : 9mA
Amplification factor : 20
Heater-cathode voltage : 90V

Characteristics-Average characteristics
Figure 3. shown typical curves of plate currents of grid voltage for several values of plate voltages. It is an alternating-current filament supply.
Limiting Operation Conditions for Safe Nor simultaneous ratings
Maximum plate voltage : 300 V
Maximum Grid voltage : -50V
Maximum Grid voltage : 0V
Maximum Power of plate : 2.5W