If you're familiar with DTL (Direct-to-Lung) or sub-ohm vaping, you'll know that this vaping style tends to consume a lot more vape juice than your average pod vape will. So, when TPD and TRPR set the 10ml bottle size limit on E-Liquids, sub-ohm vapers needed to find a workaround.
Shortfills are a solution to this, allowing sub-ohm vapers to stock up on 50ml and 100ml E-Liquids without this 10ml limit. This is because shortfills come without any added nicotine. When you buy a shortfill, if you're hoping to vape with nicotine, you'll need to purchase a nicotine shot to add in there.
Thankfully, shortfills come "short filled"—hence the name—in larger bottles, leaving the perfect amount of space for you to add in a nic shot or two, depending on the size of the bottle. This makes shortfills cost-effective and customisable for DTL vapers.
If you purchase a 5ml shortfill, it'll come in a 60ml bottle, and a 100ml shortfill will come in a 120ml bottle. If you add an 18mg nic shot to the 50ml liquid, or 2 x 18mg nic shots to the 100ml, you'll get a perfect 3mg strength E-Liquid once you shake it up.