For Standard version tank:
- Unscrew to remove the top cap;
- Add your preferred e-liquid into the tank through the filling hole;
- Screw the top cap back.

For Child-proof version tank:
- Press and unscrew to remove the top cap;
- Add your preferred e-liquid into the tank through the filling hole;
- Press and screw the top cap back.
Note: The pressing and twisting operations in each step are performed simultaneously.
