About TSPU

As we all know the recent mass blocking of social media sites is done by TSPU boxes. But little is known about the technical details of these DPI boxes (for example, what are they - netfilter? Are they on-path or in-path?).
I’ve been trying to gather information online, but so far what I got is very limited. Two posts [1] [2] about Roskomnadzor’s order for ISPs and two articles [3] [4] on interviews where TSPU got (briefly) mentioned.

Is there any other source of information on the technical aspect of TSPUs? Any pointer is greatly appreciated. Thank you in advance.

Hi, here you go RDP.RU | EcoFILTER 4160 | купить в Телекомсервис

And one more URL-фильтрация - Service Gateway Engine - RDP

Thank you all for the reply.
Do you have a source that states that TSPU boxes are these “EcoFilters”? I thought TSPU devices are made by RDP.RU specifically for Roskomnadzor so I expected they won’t be found on the market?

Yes, I have the manual which was handled to the ISP after TSPU installation, and that’s a regular EcoFilter.