THOMSON - CSF

5840 - EF732 - EF762
beautiful sounding French tubes

The 5840 is a subminiature pentode tube.

The 5840 tube is electrically similar to the AC701K tube used in a lot of famous vintage Neumann, AKG Schoeps and Telefunken microphones (M49 M269 ELAM 250 KM254 and many others) 

When used in triode mode 5840 tube sounds very close to extremely expensive and rare AC701K tube
Perfect choice for your
MOJAVE MA-100 MA-200 MA-300 MA-1000 MA-202ST microphones
Blackspade Acoustics UM17 UM17R microphones
Chameleon Labs TS-1 TS-1 Mk II microphones
Bock Audio 50 microphone
Peluso TR 14 microphone
McHugh Military AMM-68 microphone

Royer Labs SF-24V R-122V microphones

Sterling audio SM-69 microphone

Altec-Lansing M-20 M-21 microphone

Soundelux e49 microphone

TELEFUNKEN AK-47 MKII 
Great choice for DIY microphone constructions
very high emission, tube tested:

Ia = 12,5mA

where 100% for the new tubes is 7,0 mA
code FSE 8135,  made in 1981 in France
at  Saint Egreve (Grenoble Alpes) tube factory
The NF Triangle stamp 
is a French Mark of compliance, covering aspects such as safety, quality, usage ability and performance.
Tube's selected from the large military stock (over 1000 tubes) and was never used for sure

the tube was tested in Mojave MA-200 microphone - very low noise and great sound
I always send the tubes by priority registered mail with tracking number within hours after receiving payment