^^the Protanks have the single coil but unless you drill them out (and a drilled out air control flow valve is even better) more air, more vapor. The aerotank has dual coils (so does the aerotank V2 and I love 'em) some say it's "more harsh" more "throat hit" but honestly not a heck of a lot of difference, in price and vapor imo other than with single coils batteries last longer and eat less juice.