The Universal triode from Myers is of double ended construction to reduce inter-electrode capacitances and was a successful product. It was also known as the RAC-3 and is a bright emitter. It was later superseded by the dull emitter Dry Battery valve.
Initial introduction was in Canada in 1922. However Myers had worked with De Forest, RCA etc in the USA making valves and infringing patents along the way. Technically a good valve the company moved back to the USA after the expiration of the De Forest patents but legal action by RCA for back royalties drove the company to bankruptcy.
The attached .PDF file is a reproduction of a 1924 article from Wireless World.
The red end has connections for the anode and the f+ connection. The black end has connections for the negative end of the filament and the control grid.
Looking at the evacuation pip. The electrodes are held in place within glass beads.