It's fine. Same stuff everybody else in the industry uses. It's just silica wick. I don't know why they call it fiberglass, maybe silica is some kind of dirivitive of fiberglass, idk. but what you need to understand is that if you don't want to use this stuff, you might as well just quit vaping, bc it's an industry standard, used in carto's, ce4,5,vivi novas,iclear30s, and billions of other things. Nobody seems to have died yet either. I will say though that i understand it makes it confusing when this is labeled as fiberglass when everywhere else is just called silica. But i have some of this, bought from here, & it's just like any other silica I've used, except they mislabeled it as 3mm when it was really a 2. This is the cheapest you'll find it anywhere too