Variable Voltage, or VV, is a feature found in some personal vaporizers that allows the user to manually adjust the voltage being provided to the atomizer (or cartomizer) heating coils.

Generally, the voltage circuit will allow for a range of voltages from and more commonly around 3.0 volts and up to 6.0 volts – this being the output different variants in battery types and sizes. Some, however, may have a boost circuit that will allow for higher voltages.

The advantage of a variable voltage device is that it allows the atomizer (or cartomizer) to be used at its optimum level (in terms of its output in watts) and so will give the user of the device a greater range of control over throat hit and vapor production, according the to resistance of the heating coil and PG/VG ratio of the e-liquid being used.

You can see variable voltage being used in the most popular devices today, such as the LavaTube, Provari and eGo-C Twist among many others.