Once received, they are ready to be boosted in nicotine with nicotine boosters (not supplied). The longfill is the same principle, but a little different. Inside? You find 20 ml of overdosed flavours. And it's up to you to add the PG/VG base of your choice, as well as your nicotine boosters (not supplied). The longfill allows you to obtain a higher nicotine level than with the shortfill.