Looking for Info on STAX DMA-X1

Hi All,
I recently acquired a pair of vintage STAX DMA-X1 mono FET amps and matching pair of Electro-static speakers.

I'm looking for some info on the amps as they don't appear to have the enclosures on casters that are usually seen on the internet. I think these may be custom built enclosures. Plus the inputs look to be 1/8 inch jacks, which may also be a custom thing.

Also, I'd appreciate if anyone can give me an idea of what these are worth today. These are in pristine condition but since my studio is already jammed with gear, I don't have room for these and will probably sell them.

Thanks
Ray