The classic 807 beam tetrode valve is unusual in still being designated as current production in the 1960s and having a five pin base. The 807 was normally run hard and different makes of 807 held up better than others. This exhibit looks to be new and unused. It was not made in the UK and has the pejorative term Foreign printed on the glass. Probably made in the 1960s.
The parameters given are for single ended use. When used in a class AB1 as a push pull pair with 600 volts on the anode an output power of 65 Watts was normal.
The anode is insulated with ceramic spacers.
The elliptical lower screen is indicative of the 807 design.
The five pin base with pristine pins. The pins are slit and bowed slightly to grip the valve-holder.
The upper screen and copper lead to the top cap. The anode is a box with extra flanges at the main heat producing face.
The classic envelope is 50 mm in diameter, and excluding the UX5 base pins is 119 mm tall.
References: Data-sheet & 1040. Type 807 was first introduced in 1938.