Shortfill e-liquids are bottles of vape liquid that contain zero nicotine. They have been slightly underfilled in order to make room for nicotine shots. Shortfill e-liquids allow vapers to purchase larger bottles of e-liquid instead of buying tens of 10ml TPD compliant e-liquid bottles.
Since May 2016 the TPD (Tobacco Product Directive) has restricted the sale of nicotine-containing e-liquid to a maximum size of 10ml. The shortfill method has allowed the vape industry to flourish in the UK and EU.