The UAF41 is an early all glass valve introduced in 1948 together with the EAF41 and consists of a single diode and a variable μ RF amplifier pentode in a single envelope.
The valve is screened and the envelope has the moulded glass pip for pin registration in the metal skirt of the base. The first B8A valves had metal skirts fitted with built in locating pips and spigots to guide the valve into its base.
By the early 1950s the B8A valves were being phased out in favour of B9A and B7G based valves.
The base connections differ from the UAF42 in that the suppressor grid is connected internally to the cathode.
The diode anode is mounted above the pentode.
Inside the screen can be seen the wire grids of the pentode. The anode is formed as a pair of plates and strapped together top and bottom.
A closer look at the diode anode.
The thin glass tube envelope is 20 mm in diameter and, excluding the B8A base pins, is 53 mm tall.
References: Data-sheet & 1040. Type UAF41 was first introduced in 1948.