Highly desirable, mega rear OSRAM BVA U52/5U4 rectifier tube, made in UK. 
Clear glass, perfect getter, no signs of usage.  
This Osram U52 5U4G has been tested as follow:
5 volts filament with setting at 120mA
The results are
A1 = 100% emission
A2 = 100% emission
Matched pair anodes and the tube is 100% perfect.