A vape pen is a slim, cylindrical vaping device that resembles a traditional pen in shape and size. Most vape pens use a rechargeable battery paired with pre-filled or refillable pods containing e-liquid and a coil. When you inhale, the battery heats the coil, which vaporizes the e-liquid.

Vape pens are the most popular form factor for new vapers because they're discreet, easy to use, and require minimal maintenance. The term overlaps heavily with "pod system" — most modern pod vapes are pen-shaped. The key distinction is form factor: if it's slim and cylindrical, it falls under the vape pen category.