Suin SA1000 series specrum / network analyzer

[slugrustle]

While looking for a spectrum analyzer / vector network analyzer that has a frequency range extending to <1kHz and preferably a switchable 1MΩ / 50Ω input impedance, I stumbled across the Suin SA1000 series (SA1030, SA1080, SA1140).  Does anyone here have any experience with these products or this brand?

https://www.suindigital.com/frequency-characteristic-analyzer/560.html

These analyzers seem to be available from stratatek, although not the SA1216 or SA1220 models listed on Suin's website.

https://www.stratatek.com/product-page/suin-sa1000-series-frequency-characteristic-analyzer

I have reached out to both Suin and Stratatek to ask for more detailed specifications and/or a datasheet or manual.  If they send a file and allow it to be posted here, I'll add an update.