[Hammarlund] Speaker Query

[Oliver J. Dragon]

Good Morning,

Are the Hammarlund S-100 and S-200 speakers fully enclosed, i.e., is there 
a back panel? If so, what is the material?

Also, I can't find the definition of the tube designation 'WA' as in 0B2WA. 
In fact, I can't find
an entry for tube types 0A1, 0B2 in my 1954 RCA Receiving Tube Manual. It 
may very well be
there, but I don't see it.

Any help greatly appreciated.

Ollie.