The Telefunken RL12 P35 is a German transmitting pentode dating from the WWII era. One of the top caps are clearly marked A for anode and the second top cap is taken to the suppressor grid.

The base is of a bayonet locking type with five small base pins. The skirt hides the electrodes and is indirectly heated with a circular cathode tube.

The picture above shows the valve turned through 90 degrees.

For further information click here.

The wide glass tube envelope is 48 mm in diameter, and excluding the base pins, is 145 mm tall.

References: Datasheet.

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa
	12.6	0.63	800	200	-	150

Thanks to Frank Philipse for supplying the above PDF datasheet