The PP2018 output pentode was introduced by Tungsram in 1932 with a five pin and side terminal base cap. The B7 based version followed in 1933.
The identification is etched into the dome of the envelope. The top mica holds the electrodes. Attached to the main supports are small mica pads that fix the valve into the envelope.
Looking up from the base. All three wire grids are visible.
The classic envelope is 45 mm in diameter and, excluding the B7 base pins, is 101 mm tall.
Reference: 1043. Type PP2018 was first introduced in 1932. See also1932 adverts.