The Yocan Handy is the latest, smallest 510 cartridge battery on the market. With it's large hole, the Handy fits most any standard 510 cartridge (up to 11.5mm diameter). Just screw the included magnetic adapter onto your cartridge and drop it into the device. 5 clicks will turn the Handy on or off, additionally 3 clicks will change your voltage setting. The Handy has three voltages; low (white), medium (blue), and high (green). We recommend using the lowest setting that provides vapor in order to extend the life of your cartridge and to avoid burning. The Handy features a 500mAh battery, which is impressive for its size, to provide enough charge for multiple uses and likely multiple days of normal usage. Even if your battery runs out, the micro USB port makes the Handy extremely convenient to charge. Stop in today and check out the latest Yocan has to offer!