Due to TPD (tobacco products directive), new regulations have meant manufacturers can now no longer sell nicotine containing e-liquids in bottles larger than 10ml. (It's also the reason why vape tanks can now only be 2ml). To get around this and continue giving vapers the best value for money, shortfills were invented.
Shortfills are larger bottles of e-liquid and contain zero nicotine, the bottle is 80% 'short-filled' with flavoured e-liquid giving you space to add your nicotine.
Starting out in a 60ml bottle with 50ml of e-liquid, Shortfills are now available in a range of sizes from 25ml through to 200ml bottles.