The AV11 is a high voltage half wave rectifier developed in Australia during WWII when supplies of rectifiers became difficult and higher power radar sets were required. The design and manufacture of both sets and valves was completed in Australia. Full details can be found in the attached .PDF file that comes courtesy of the Museum of Victoria.
The maker AWV is the Amalgamated Wireless Valve Company, Sidney, Australia.
This exhibit does not contain a Type designation on the envelope but the design matches the AV11.
The Radiotron Australia brand on the base cap.
The very high voltages demand good insulators, hence the glass rod supports.
A closer view of the oxide coated ribbon filament.
On test the filament draws 1.75 A at 2.5 Volts.
The classic envelope is 51 mm in diameter, and excluding the UX4 base pins is 125 mm tall.
Reference: www.museumvictoria.com.au. Type AV11 was first introduced in 1941.