I have a brand new Bose PRU 57 headset for sale. Feel free to email me at pittles@gmail.com if you are interested. I also have a set of new dave clarks for sale too. Can send pictures of both.
Brand new Dave Clark's going for $25 on ebay?? I guess I'll hang on to them.
As for the PRU 57 headset, pretty sure it is for aviation...
A “variable family” nomenclature for the ANR
system has been established and designated as
“headset electrical,” active noise reduction,
PRU-57(V)/P. The four versions currently
on contract are the:
(1) HGU-55/P helmet version preliminarily
designated as PRU-57(V)1/P, (2) the headset
version preliminarily designated as PRU-57(V)2/P,
(3) the F-22 aircraft version preliminarily desig-
nated PRU-57(V)3/P and (4) the helicopter
helmet version.
Found them in a closet in a house I was renting a few years ago, just trying to get rid of them.