The nib of the bottle breaks away for easier filling.
Here are some easy to follow instructions for our short fills;
18mg Nic shots
50ml zero nic e-liquid – x1 10ml @ 20mg = 60ml 3mg
50ml zero nic e-liquid – x2 10ml @ 20mg = 60ml 6mg
(you would need to decant 10ml to make room for the extra bottle of nic)