The EB34 is a double diode. The glass envelope has had its external screening paint removed and we can see the construction.
The two small diodes separated by a central screen.
A closer view. The active area can be identified by the heater connections. The rest of the anode is to dissipate heat. The anode is held in the correct place by the two support rods. For the left hand diode the supports are on the left and the working section is on the right. The other diode is identical but turned through 180 degrees. The details of the cathode connections can be seen.
The wide glass tube envelope is 30 mm in diameter, and excluding the IO base pins, is 60 mm tall.
References: Data-sheet, 1040 & 1043. Type EB34 was first introduced in 1941.