The A2134 pentode is an audio power valve. In class AB1 a pair of valves in push pull will deliver 13.3 Watts. The input needs 30 Volts peak to peak and the anode load requirement is 7,500 Ohms.
Also the data-sheet specifically mentions suitability as a series pass valve in stabilised power supplies.
The A2134 looks to be slightly higher in output power compared to the N78. The N78 runs hot so the additional cathode emission of the A2134 suggests that this too would run hot, especially as a series pass valve.
In Class A, triode connected, the valve will generate 2.6W at 1.4% distortion.
Lorenz is a German company that was taken over by the American ITT corporation.
The side view gives few details of the construction.
The control grid is wound on copper supports and has heat radiating fins attached at the top.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 63 mm tall.