I just got a Meinl Profile Hi-tech 18" Crash, not because I needed it, but just because the price was way too low to refuse.

Surprisingly enough I really like the sound, more so than my Paistes I have right now. So I was considering buying some more Meinl Profile cymbals, but noticed that there seem to be 3 different types of Meinl Profile: Hi-tech, Velvet rock, and Volcanic Rock. Does anyone know the difference between these cymbals? Are they just some fancy names for three weight classes (like for Paiste: medium, heavy, power etc.)?
Would be nice if someone could give me some input on this.