You'll forget the other slim pens you smoked before, because this new adjustable twist battery blows others away. With the new preheat mode and temperature settings ranging from 3.3V to 4.8V, the Slim Pen Twist Battery is perfect for anyone just starting to use cartridges or your everyday veteran. . 15 Seconds Hold Time and an Auto Safety Shut off helps Preserve Battery life. Fits all 510 Thread and has a USB Smart Charger Smart USB Rapid Charge.