"Unigrit" is a
Meguiar's trademark. Nobody else sells "Unigrit" papers (not legally anyway).
Actually,
Meguiar's doesn't make the papers, they just have exclusive rights to sell them in the US. They're manufactured in Japan by Nikken.
Nikken's papers are superior to others because of the extremely high consistency of their grit particles. This makes the sanding scratches they leave much easier to buff out than scratches left by other companies' papers.
PC.