Made by Magnavox Sydney, I suspect actually a Philips product (they bought Magnavox USA)
These are used electrostatic tweeters extracted from a working Kreisler radiogram
Magnavox Electrostatic Tweeter
Model: E3.5
Made in Sydney - 1950's - 60's
These electrostatics usually have a high polarising voltage applied to one side and the other side of the speaker goes to the output tube anode, via an electrolytic.
If in circuit, be extremely wary of touching the speaker terminals - you will get "kicked"
DC resistance test is infinity, which is good - at least the dielectric material is still insulating, probably a foam though (it has a habit of disintegrating over the years)
I have no suitable equipment with a decent B+ supply and single ended output tube so I cannot test any further.
At the time of removal from the radiogram, they were working fine - that was about ten years ago!
All metal construction, pressed together and with the horrid rivets - I would imagine that any attempt to "go inside" will destroy the speaker for sure.
93mm diameter x 16mm height
Cosmetic condition is very good to excellent - one speaker has light rust on the rear outer rim, that's all and I couldn't image this would affect the speaker operation.
Sorry but I am only able to offer these untested prior to advertising, just made the very basic DC resistance test and nothing more.
