The 3E29 is closely related to the 829B American pattern VHF double tetrode and has the same pin connections. However, the 3E29 is specifically designed for pulse modulator service rather than for use as a VHF PA.
The National Union maker name and Made in USA.
The lower anode supports are surrounded by ceramic insulators. The centre of the working face of the anode has supplementary heat sinking in the form of three extra folded fins at the point of maximum heat generation.
The ends of the carbonated anodes. Within can be seen the bright beam plates.
The wide glass tube envelope is 50 mm in diameter and, excluding the B7A base pins, is 92 mm tall.