Here is a rare tube — a Marathon MX-280 Globe #80 rectifier tube featuring MESH PLATES construction! Not only that, but each section tests very strong Emission, comparable to an NOS #80!
In 18 years of collecting, I do not remember ever seeing another Mesh Plates #80 tube. Look at that Glow! You can see right through the Mesh Plates into the filament!
It also has an Engraved-base which reads: MARATHON MX-280.