The DV-3A is a dull emitter triode for use with dry cells powering the filament. The specification is close to the UV199 - PDF attached.
The wider bulb allowed the electrodes to be mounted horizontally.
The paper label seen on the glass was introduced about 1925.
Thanks to Joe Gruber for sending the image.
The wide glass tube envelope is mm in diameter and, including the UV base pins, is mm tall.
References: Data-sheet & Joe Gruber. Type DV-3A was first introduced in 1925. See also 1925 adverts.
Absolute Maximum Operating Conditions¶
Updated September 22, 2020.