I really like this RTA (Rebuildable tank Atomizer). I'm using dual Ni200 coils and cotton wick @ 0.10ohms 250°C. Something I picked up on though, it has the airflow valve in the tank (maybe most do). It tells you to shut the valve for refill but unless you want leaking keep it shut, opening from time to time to allow fluid in and air out. You'll easily know when to open, once the air escapes close it back or it will leak with that valve open. FYI only Great taste, good clouds, tank filled last a day or two, battery consumption a little high but OK on this dual battery mod (Sigelei FuChai 200w VW/TC).