Warhawke (sir or Ms.?) dual coils are like running to cartos are once, instead of having a single heating coil, it's two running in parallel. They do go through juice faster because of this, but they also don't burn the filler as easily due to them being medium to high resistance coils instead of one low resistance coil. The draw back is they do put a lot of strain on the batts.
CE2's are technically dual coil as well, but since they have no filler they use a different wicking system. They are hit and miss, people who can get them to work love them. Those who can't, hate them. Still put the same stres on the batts though. Hope this helps.