No idea, but some of them really suck. Miso mayo chicken is pretty dry, same as their tuna which is like a sand filled tuna sandwich, completely unlike anything I had in Japan. The only one I can somewhat enjoy is the pork with boiled egg, but that's hardly what I think of as a traditional onigiri.
Fujiya onigiri are slightly better but not by much. I miss 7-11/Family Mart/Lawsons onigiri from Japan which had tender tuna flakes, creamy mayo, and fluffy rice. That's on the low end of the spectrum for onigiri in Japan too.