T3x2 flat press subminiature pentode intended for use as audio or DC amplifier in wearable or portable instruments, including hearing aids.
Pinout: 1(red dot)=anode, 2=screen, 3=filament, 4=g1, 5=filament Vf=0.625V, If=20mA. Va max=45V, Vsg=45V. No power limitation, since you can't draw enough current to do anything bad.
Pentode mode: gm=160uS. Triode mode:gm=250uS, Ra=35k, MU=9.
Reasonable amplifier bias points: Pentode: 0.7V bias. Va=22.5V, Vsg=27V, Anode supply=45V. anode resistor=180k. Ia=.12mA, Isg=.06mA. Triode: 0.6V bias. Va+sg=22.5V, Anode supply=45V, load resistor=100k, Ia+sg=.2mA.
The tube 6088 has the same pinout but Vf=1.25V at 20mA and many other differences in operation.