The VT-84 is also marked as type 84 and 6Z4. It is a low power indirectly heated full wave rectifier with a common cathode tube that runs vertically through both pressed anode cavities.
The stacked anodes mounded on the common cathode tube.
A closer view of the internal structure. The anodes are identical and the off-centre allows one to be rotated through 180 degrees relative to the other. Thus we can see both sides of the securing stitch.
The classic envelope is 38 mm in diameter and, excluding the UX5 base pins, is 89 mm tall.
References: Datasheet, 1040 & 1043. Type VT-84 was first introduced in 1937.