To make use of a cart pen and THC cart, the user only screws the THC cart onto the pen. The moment related, the pen heats up the oil while in the cartridge, either through a button press or by drawing about the mouthpiece, depending upon the design. Discreet Style: https://thc-cartridges08652.pages10.com/the-fact-about-thc-cartridges-that-no-one-is-suggesting-68087320