The DEP240 is a two volt audio output triode for use in battery equipment. When introduced it was described as a Super Power output valve with the new filament.
The identification is at the top of the dome and quite faint. The words at the top of the circle are Made in England.
The balloon envelope is 46 mm in diameter, and excluding the B4 base pins is 89 mm tall.
References: 3002 & 1043. Type DEP240 was first introduced in 1927.
Absolute Maximum Operating Conditions¶
Updated October 05, 2018. shape:balloon construction:pinch type:triode age:1920.1930 base:b4 heater:2.0v pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f