The Hivac XW or XW2.0 or XW2.0V is a miniature battery RF pentode that Thrower describes as a post WWII design.
The Hivac name can be seen etched into the glass. Within the anode is made of mesh and the connection between the control grid and the top cap is clear.
Here, above the top mica, can be seen the filament tension spring and the single hairpin inverted V filament strand.
The thin glass tube envelope is 18 mm in diameter, and excluding the Sm5 base pins is 64 mm tall.
