Review (3/5): Not universal
I bought this after my Deva trained/curly-specialist stylist used it on my hair. It doesn't move the hair at all as it's drying, keeping down the frizz. Slightly deep, to dry more hair at a time.
But sadly this does not fit my "Revlon Perfect Heat" drier. The drier's end has a ridge at the last 1" or so that's smaller than the rest of the nozzle. That last inch fits, but the rest does not, so it won't stay on. This diffuser requires that more than an inch of the drier be inserted, as the rubberized treads inside that make it a flexible fit are located further down the barrel. Considering I don't have an unknown or rare brand drier, this diffuser should probably not be called universal. I considered buying the bio ionic drier to go with it, but not at that price.