The 35T is a directly heated power triode for use at up to 100 MHz, at maximum input one 35T can produce up to 235 Watts of RF. The anode is small but can dissipate 50 Watts.
The anode side view showing the flanges presses into the metal. A locating pip can be seen on the right of the ceramic base shell allowing a bayonet base to be used.
The grid is a cage of vertical rods - seen in the image as dark lines with an open pitch helical wire running up the outside. The filament is an inner helix. The greenish/yellow glass where the anode pin passes through the envelope is uranium glass.
The wide glass tube envelope is 45 mm in diameter, and excluding the UX4 base pins is 124 mm tall.
Reference: Data-sheet. Type 35T was first introduced in 1951. See also1951 adverts.