[Milsurplus] Tube id

[telegrapher at q.com]

I mentioned a while back about a Navy tube with a Navy number on it.  I found another one, 845 marked on the base but i doubt that's correct.  It appears to have a 2.0V filament.  Someone wrote on the side of the bulb "84" but that number doesn't seem to check out either.  Certainly lights up the filament way to bright in the tube tester.  What is the correct id on this thing?  

Larry
W0OGH