fearless ive been doin this for awhile now ... look at this thread its 2 yrs old .... the screwdriver has a 8 to 12 hr battery and you get 2 ... the vapor is so much its overwelming sometime.... if you dont want something as big ... get the tornado tank regular or standard ... go to the wicked website ... trust me the screwdriver has the most of everything .... and the website has hundreds of flavors plus a mixing kit to make your own .... but i recommend the sd mk2 with the tank conversion .... 2nd woulkd be the tornado tank .....