The 804 is a transmitting pentode normally used as a power oscillator. The anode dissipation is about 50 W for intermittent service and 40 Watts for industrial service - ie a greater duty cycle. An output of 28 Watts or 16 Watts could be expected at up to 15 MHz and with reduced ratings it could be used to the low VHF.
The filament is thoriated tungsten.
The central box anode is made from thin sheet metal. Considerable bright screening extends either side of the anode.
The anode connection is made to the side flanges.
The top ceramic insulator showing the pair of helical filament tension springs.
The bright screens connect directly to the narrow pitch box shaped suppressor grid.
The wide glass tube envelope is 51 mm in diameter, and excluding the UX5 base pins is 200 mm tall.
Reference: Datasheet. Type 804 was first introduced in 1940.