There i also this one from Optivelox
http://optivelox.50webs.com/ss0x/ss07.htmlIt's not a binaural system but an audio interface to be used both with a stereo mic supplied by them or with whatever else stereo mic terminating with stereo minijack.
The firm is located in italy not far from where I live ( 100 km), but it seems that these product never get on the market. They launched a fundraising campaign last year for this product ( the one I posted) but I don't think they raised what expected.
When I saw the announce in 2016 I wrote an email to them in order to have some more infos, looking for an easy way to improve the audio in smartphone videos.
What they answered was that this USB interface can't directly record on video app but, in parallel, on a dedicated audio recording app ( probably also with other audio apps). So you would have your smartphone doing two recordings at the same time, a "normal" video recording with internal mics and a better audio recording, to be coupled in post.
So, apart from eventual crashing problems due to a huge he phone has to bear vs. the advantage of having a single device, it seem this toy doesn't mean a real step-up compared to a separate audio recorder.
This is referred to the product I posted - SS07 - not to this SS08; however, it seems to me they share the same concept.