The KT35 is a kinkless tetrode audio output valve from M-OV designed for series heater chains in universal AC/DC sets. The heater value given is for the two halves in parallel. In series the KT35 has a 300 mA heater.
By 1951 it was regarded as obsolescent.
For the rated output power the valve should be operated with an anode load impedance of 4,000 Ohms.
The L shaped fins are control grid cooling strips and the S shaped strip is a screen connecting the cathode to the beam plates.
A μ-Tracer plot of the characteristic curves for this exhibit. The characteristics test to 101% of the nominal values in the specification.
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 104 mm tall.