This looks like a meter for a Bendix ADF, maybe model MN-26 or MN-28 ?

Box front reads       3F-1010-7

                                                3

                                          010529

And in the upper right same surface, in pencil,  9544.

Box top reads SERVICEABLE PROPERTY  and in stamped square, 

ACB

INSP

  12

Also, a conversion sheet with info on how to use as beam antenna direction indicator.

Do you know more ? Have good guesses ?

I do not need this thing.

-Hue Miller