This is JUST a single twist battery, good for replacement or if you just want to have a twist in your ecig collection! This battery has the twist variable voltage function. At the bottom of the battery your simply turn the dial to the voltage you want and vape! Voltage can be adjusted on the fly, to suit your vaping preference. 5 click protection feature. If the button is pushed 5 times it will turn the device off to prevent accidental firing. Press 5 more times to turn the device back on. This single battery is 650 mah. So even with the voltage turned up this battey will last a good portion while! Note: This is JUST the battery, it does not come with any atomizers, cartomizers, cones, or drip tips and no charger. You will need all those pieces in order to use this.