[ForSale-Swap] National MB-40SL Multi-band tank, Cardwell (?) variable "condensor" (capacitor)

[Al Gulseth]

Attention antique collectors and boatanchor types: more "goodies" as I 
continue the slow process of going through my dad's stuff after moving him to 
assisted living.

1) The National MB-40SL Multi-band tank "is intended for use in grid circuits 
with approximately 20 watts input and in final plate circuits of transmitters 
when the power input to the stage does not exceed 40 watts loaded."

The unit is in very good condition overall with the only real issue being that 
the plastic feed through insulators (3 total - look like clear tip jacks with 
the contact mechanism removed) are slightly cracked/distorted from age and 
soldering. Includes worn but intact original paperwork "Application notes for 
the National type MB-40SL Multi-band tank" dated 9/29/53. Package includes 
two (I'm guessing similar vintage) knobs. 

I have gathered that this is a fairly rare item but I have no idea what it is 
worth. Therefore, I will entertain offers, both cash and/or swap (preferably 
QRP stuff but might consider other items.)

2) What appears to be a very old (maybe 1920's -30's?) Cardwell (?) variable 
capacitor, 2 X ~ 200 pf with an old ~2" diameter knob that has a fancy Coke 
bottle shape (for lack of a better term) pointer. No manufacturer name on it, 
just a c-shaped logo inside a circle - the logo has an arrow at the 
"northeast" end of it and a capacitor symbol ("=") in the middle ("west" 
side) of the "c". Other than that, it says "Made in U.S.A" and "U.S. Patent 
162639". The stator insulators are strips of Bakelite or similar that the 
stators are mounted to with screws and nuts. (I.e., very simple manufacturing 
process.)

Again, I have no idea what this is worth - offers?

TNX/73, Al