The QV04-7 single beam tetrode is housed in a 1947 early all glass envelope design. The output is modest and the dissipation high in relation to the output.
The locating flange on the spigot.
The lettering is feint but this is a Mullard Valve. Above the lower mica can be seen the copper of the control grid supports and the beam plates.
The wide glass tube envelope is 32 mm in diameter and, excluding the B9G base pins, is 59 mm tall.
References: Data-sheet & 1040. Type QV04-7 was first introduced in 1946. See also1946 adverts.
