This exhibit has no markings. An attached paper label identifies it as a Philips T II rectifier. The filament connects via the ES base. The anode connects to the bayonet cap.
The AU3 Army rectifier has the same appearance. It has a filament that runs at 5.5 Volts and 1.5 Amps.
The filament is a single hairpin. The anode is clamped to the pinch tube at the opposite end. The evacuation tube can be seen as a pip on the side of the middle sphere.
The filament is held some distance from the anode, suggesting a high voltage device. The filament when run at 2.5 Volts takes 1.5 Amps and lights to the orange of thoriated tungsten. 2.5 Volts was the original American standard for AC valves.
The filament tension spring fixed to the glass pinch at the anode end.
The balloon envelope is 76 mm in diameter, and excluding the base pins is 195 mm tall.
References: Observation, 1003 & label.
Updated July 19, 2014. shape:balloon construction:pinch type:rectifier.hw age:1920.1930 base:es pin: