...which look like this:

You may need a measure of good luck.

Many walkmen have outlived their original headphones...

Don't worry, I have once bought a pair of Aiwa HP-M10 headphone and I accidentally killed both the speakers when trying to measure them with the multimeter. (Coz dc voltage may burnt out coils of the speakers) - never attempt to do that!! Fortunately nowadays there are many headphones made in China that using the same diameter of these vintage headphones, I bought a pair of them and transplant the speakers over to my Aiwa and able to revive my M10 finally. But it require great patients to do the soldering of the fine wires.

The Aiwa HP-M10 headphone

Here's how the speakers look like. You can even purchase them in the net from the Chinese dealers.

http://ruibocn.en.alibaba.com/...adphone_speaker.html

yeah those fold away headphones brings me memories of my aiwa walkman 

I have a pair of aiwa headphones, but I think they are not foldable!

I own a pair like these in very good shape.

I too have been looking high and low for these head phones, good luck Minty.  These are for the Aiwa HS-J600 right??