I think its some kind of hearing aid?
" I haven't seen one of these before so apologies if I get details incorrect!!
This is an Acousticon Dictograph made by the Dictograph Products Corporation successor to General Acoustic Co. in New York.
The original box contains the recording device, an earphone/microphone, original cables, headset and a blunt, shaped blade in a handle. The sections for the earpiece and recording device are baize lined for protection. Box size 7.5" x 4.5" x 3".
I am guessing that it is some sort of wire recording device. The main piece has a small belt clip at one end and a volume control at the other.and the other side looks like the recording area. There are 4 screws to access this but no obvious recording surface (like tape).
The earpiece fits on to the headset - there is space in the box for the battery. There is an on/off switch on the earpiece.
The blade on the handle also fits into the earpiece. This might make the earpiece into a microphone.
I have found the same product on an auction site but there was no helpful description!!
The manufacturer also produced hearing aids, telephone switchboards and eavesdropping devices. The technology looks similar to a hearing aid but not identical.
Approx price to Australia/USA will be about £10.50
This item is being sold to support Lesmahagow Parish Historical Assn which has recently effectively been evicted from its archive premises by S. Lanarkshire Council."
The 'recording' box contains a carbon microphone and possibly the battery, although that might have been kept in the outer carrying case.
The 'blade' is a handle so you can hold the earpiece in your hand, as an alternative to using the headband (ladies' hairstyles).
Electrically it's a simple series circuit of transmitter and receiver.
This is an early hearing aid.
Here is a synopsis of the person behind it...
There were versions that were leased out for bugging and other detective uses.