You've probably already discovered when you twist and hold the ring to the right, it changes between VV, VW, and the custom settings. When set on VW you twist and hold the ring to the left, it changes what the left side of the display shows: ohms/volts, time/date, puff counter. I set it on ohms/volts, which shows you what voltage the variable wattage setting assigned for the resistance and what that resistance was when read. One short click of the fire button will show the display without changing the power setting.