Ahhhh... I got my answer from the Tasty Vapor site (thanks, mpetva)... Doublers are "Made for the sole purpose of thinning out your high nicotine fluids". Got it... basically "double the flavor" concentration, so to speak, as it's meant to be cut.
So I guess my next question is whether it's too strong to vape on its own? I obviously wouldn't be adding any nicotine liquid, but would I still need to thin it with water or something? Or have you guys vaped it straight up? Or was that the original question? LOL
But damn... 120ml for $12?! I've been throwing money away on 0mg juice!
it's the same flavor as the juice with nic, so when you cut the 24mg juice to 12mg you do a 50/50 with the doubler, so you maintain the same flavor (vs just cutting the 24mg with regular pg or vg).