This is a variable volt APV made by Smok Tech that takes vaping to the next level. This is really a variable power mod because you have the option of adjusting either your voltage or your power (watts). The Zmax adjusts from 3.0 to 6.0 Volts in .1 volt increments or 3.0 to 15 Watts in .5 Watt increments. The ZMax has a stainless steel finish and a maximum output of 4 Amps. The Rev. 2 the Zmax has one extra menu item (8) which enables you to switch between RMS and mean value voltage monitoring. The RMS mode is more accurate because it samples the output Voltage repeatedly while it is powering an atomizer or cartomizer. It is with these measurements that it is able to adjust for heat related Voltage drift.
The ZMax can read your output voltage, battery voltage and cartomizer / atomizer resistance. This APV does it all.