THOMSON - CSF 6AU6WB - 6AU6 - EF94 - 6J4 - CV2524 - 6P2
beautiful sounding French tubes
Perfect choice for your
SONY C37A microphone
SONY C800G microphone
ALTEC 21 microphone
TELEFUNKEN/SCHOEPS CM61 microphone
TELEFUNKEN/SCHOEPS CM60 microphone
PHILIPS EL6052 microphone
and in my opinion there is no doubt these are the great  tubes to replace rather poor sounding Chinese 6J4 tubes
in nowadays produced amplifiers
perfectly matched pair (2 tubes)
both tubes tested:

Ia = 5,0mA

where 100% for the new tubes is 5,0 mA
both tubes have same code FSE 8251 and were made in 1982 in France
at  Saint Egreve (Grenoble Alpes) tube factory
Black shining plate, O-getter
The NF Triangle stamp presented at the both tubes
is a French Mark of compliance, covering aspects such as safety, quality, usage ability and performance.
Tubes are selected from the large military stock (over 500 tubes) and were never used for sure
I always send the tubes by priority registered mail with tracking number within hours after receiving payment
Santic [feat. Vera Hall] – Trouble So Hard