The B349 is a low impedance high gain double triode designed for use as a cascode RF amplifier in VHF television receivers. The low voltage high current suggests a low noise design.
One of the triode sections can be seen end-on at the left of the image. The central structure is the inter-section screen.
The working part of each triode is small. The side flanges on the anode are there to help with heat dissipation.
The screen is easier to see in this image.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 46 mm tall.
References: Data-sheet & 1040. Type B349 was first introduced in 1960. See also1960 adverts.
