Vape pens or harsh oil pens are designed as a vaporizer for cannabis and oils. These handheld devices use battery power to turn liquid and oil into a vapor that is inhaled into the lungs. Vape pens are not all created equally and there are many varieties on the market designed for many different products. They are called pens because their small compact design looks similar to a writing pen. Today, we’re breaking down the anatomy of a standard vape pen meant to fill with cannabis oil.