The 6AN5WA is a special quality version of the 6AN5. The design is for long life and stable performance as one of the main application areas is within electronic computers.
The data-sheet gives applications as wide band RF or video amplifier, pulse amplifier or frequency divider. The cathode is designed to withstand operating for long periods under cut-off conditions.
As a power amplifier it can produce 1.25 Watts.
It is immediately clear that although called a pentode the construction is that of a beam tetrode. In the picture the beam confining plate is in the centre with the anode split into two separate plates strapped together. The grids are formed close to rectangular in shape and pass flat across the cathode.
The straps joining the two parts of the anode are on the left.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 48 mm tall.
Reference: Data-sheet. Type 6AN5WA was first introduced in 1957.