 DDHA would be the acronym for it. It's a very long chemical name, but that particular iron chelate is one of the best around because it performs well in a high soil pH. And what I mean by performing well is that it'll keep that iron in a plant-available form for quite a long time so that plant can take it up. So that's why I recommend using that one. There are other products with that same iron chelate in it, but in my opinion, that soy green, if you can get a hold of it, it's usually a better deal.