My understanding is that they are all basically indole-3-butyric acid or indole-3-acetic acid and that the only difference between them is a matter of concentration of this ingredient. They are indispensable for rooting woody cuttings (ie trees and shrubs) that root slowly. I have stuck everything from pointsettias to mums to all sorts of woody cuttings in the commercial greenhouse business. It was always the same stuff rootone-f and the f was for fungicide. I have heard of some hydroponic enthusiasts who add cut willow branches to their hydroponic reservoirs that serve cuttings for a few days in the belief that it will increase rooting speed.Technically there is some merit to this idea but I can not vouch for its efficacy in hydroponic systems.