[lanewinfield]

Speaking as someone who also recently purchased these panels (and read the second paragraph where they mention where they got them), they're from the company AlfaZeta.

They build and ship from Poland. They don't have a publicly available price list but they cost approx 220 EUR per 7x28 panel. Expensive, but few places still manufacture them.

If you continue reading the post, they also link out to other manufacturers including ones on AliExpress that seem to be cheaper.