The 8156 is an RF power valve designed for use in mobile equipment. The output power can be up to 21 Watts in a Class C amplifier and requires a drive power of one Watt.
This image shows the beam plate in the centre with the anode to either side.
The two part anode is formed as a flat U channel with the base facing the inner grids. The side strap joins the two sections and can be seen on the right. To the left of the anode can be seen the screen grid.
The Type designation and the letters USA appear on the dome.
The wide glass tube envelope is 29 mm in diameter, and excluding the B12C base pins is 50 mm tall.
References: Datasheet. Type 8156 was first introduced in 1964.