The EY86/87 from Mullard is a high voltage half wave rectifier. It was designed as an EHT rectifier in television receivers and instruments. The 87 variant had a defined warm-up time.
Lamba sold imported valves and so this may have been in the wrong box.
The bell anode is hung from the top connection with the heater/cathode being fixed to the base.
Thanks to Mike Tonkin for sending the Lamba Valves.
The thin glass tube envelope is 21 mm in diameter, and excluding the base pins is 66 mm tall.
References: data-sheet Type EY86/87 was first introduced in 1956. See also 1956 adverts.
Absolute Maximum Operating Conditions¶
Updated January 05, 2022.