Interesting company, thanks.
So. they can make or supply the glass. But no mention about who can make the windows or what profile you can use with their glass on the website.
Also, if this is true, the u(g)-value of ordinary 3mm clear glass double-pane with 5.8 is ridiculously high. It might be different in combination with the u(f)-value for a quality frame with thermal break. But for 5.8 I don't need more expensive double-pane windows then....