built-in program of recommendation voltage range without limit voltage , when you put atomizer/ atty ,cartomizers in to itaste VV battery , itaste VV battery will automatically identify atty Ohm, press 2 buttons at the same time near LCD screen , there is display recommendation voltage range , customers either can follow this recommendation voltage range or disregard .itasteVV battery will not tacitly approve this voltage .
for example: LCD screen show number 3.5 4.2 V, this is recommendation voltage range , you can adjust voltage follow this range , you also can adjust higher voltage ,when adjust into 5V , then actually give 5V .
The above info was posted by Bad and this was also talked about in Lord Davon's review, pbusardo's review and others. The iTaste reads the atty, and pressing the 2 buttons gives you the recommended range.