The 837 RF pentode was designed for use as a power amplifier or oscillator. The envelope has the Type designation 837 etched into the glass but on the base is also the US Service code of VT-101.
Side view of the anode showing the ceramic insulators.
Face view of the anode with the bright metal screen below the ceramic lower spacer.
The box anode with a hint of the grids within.
The top showing the screen above the top mica. The mica holds the electrodes into the shoulder of the envelope while the ceramic plate is the fixing point for the electrode supports.
The classic envelope is 51 mm in diameter, and excluding the base pins is 130 mm tall.
References: Data-sheet, 1040 & 1043. Type 837 was first introduced in 1939. See also1939 adverts.