The VT158 is a 400 watt triode produced in WWII for use as a pulsed oscillator from 590 to 610 MHz. The tube consists of 4 individual tubes connected in push-pull-parallel. It was used in the AN/TPS-3 radar system where the plates were held at DC ground and the negative pulsed high voltage was applied to the filaments. It has a mu of 13 to 16 and could produce 240 KW pulses (60 watt average). The second example is a partially complete tube under construction. The filaments haven't been connected and the glass is still open at one end. The color photo was taken from a 1946 Electrionic Industries Magazine.
Length = 8.50" Width = 8.00"
Max voltage = 30 KV peak (5 KV minimum)
Max current = 70 amps peak
Fil voltage = 10.5
Fil current = 10.5 amps