Top coiled, the part that heats the wicks is near the top of the tank, wicks dangling down into the juice (like in a C4). Bottom coil sit's submerged & has very short wicks (Kanger Evod etc) . Both are available as single or duel coil. Duel coil more heat to more wicks/juice = more vapour/flavour.
Sent from my Xperia Z using the POTV app