i frequently go at 5.5 to 6v (sometimes 7.4). recently, i've been using dual coil cartos (1.5ohm), almost exclusively at 6v. that combination, while not an atty, is unlike any other carto i've tried. i also use the iatty at 5v with a 2.5ohm coil. if you're talking strictly atomizer, i suggest hv...