The type 49 is a dual grid audio power valve for battery operation. The valve was designed to operate as a triode (g2 strapped to the anode) in Class A or with both grids strapped together in class B. The latter operation using a pair of valves in push pull.
The anode side on with the filament top support rod to the left.
At the top of the image is the filament support rod passing through the top mica. The thin vertical line is the tension spring. The grid wires appear as horizontal lines.
When tilted, the oxide coated filament is visible in the centre.
The classic envelope is 44 mm in diameter, and excluding the UX5 base pins is 101 mm tall.
Reference: Data-sheet. Type 49 was first introduced in 1935. See also1935 adverts.