How to refuel an inflatable lighter? What's the screw at the bottom? Should it be loose when reloading? What are the plus and minus signs at the bottom? !

The gas is injected from the screw at the bottom. There is a small protrusion with a hole in the middle of the screw. When filling gas, the filling nozzle of the gas tank is aimed at the small protrusion in the middle, and the gas can be filled with a hard press.

There is no need to loosen the screw when filling.

The screw at the bottom is used to adjust the flame size. Rotate left and right to control the flame size, and the positive and negative symbols represent the flame size.