The Rainbow Vision Spinner 1300mah eGo Variable Voltage E-cigarette Battery comes with a 510/eGo threading. The Spinner uses smart buck-boost converter technology allowing you to adjust the voltage output from 3.3v to 4.8v by spinning the dial at the bottom of the battery.There are 16 spaced vertical lines on the bottom spinner knob for full control of any voltage that meets your vapor and flavor sweet spot needs. The spinner volt knob on the ecig battery can be adjusted in increments of 0.1 by a slight twist of the voltage output.