Western Electric USN-CW-300B Matched Pair!!! 1950's!!! Lot no.222, 145

Here is TWO Western Electric "300B".
One bid is TWO (2) tubes.

"USN-CW-300B" is used for Military equipment.
Generally, it is said that they are high reliability and long service life.

It has been manufactured in the 1950s.
The Lot no. are: "145", "222".
And, they have a large "D-getter".

You can use these tubes as "Matched-pair";
The difference of Plate current is ONLY 2mA!!!
I asked to measure my tubes to Third-party organization, that the famous vacuum tube dealer in Japan.