It's a pen. No - it's a battery. Wait.. it's both! The Penjamin Cart Pen a low-key writing pen and cart battery built in one. 
Embrace the fusion of discretion and functionality with the aromatherapy Cart Pen by Smyle™ Labs. With its patented design that mirrors a traditional pen, this cartridge writing penjamin takes your experience to new heights of convenience. Compatible with both 0.5g & 1g cartridges, this premium battery is made of high-quality materials. Adjust the voltage to tailor your sessions to your preferences, and use the preheat function for optimal performance.

Features:
Looks and writes like a real pen
High-performance 510 cartridge battery
3 adjustable temperature settings
Preheat function for best performance
Compatible with 1g and 0.5g cartridges
Includes Mirco-USB Charging Cable

To write, screw the bottom part of the pen in a counterclockwise direction.
To rip, take the rubber garment off the top part of the cartpen, insert and screw any 510 threaded cartridge in. Put the rubber garment back on, covering your cartridge tip until the mouthpiece tip pops out. Click the button that is placed under the pen clip 5 times to turn the cartpen on. Click 2 times to preheat, and 3 times to choose the temperature you would like.