Quick Fill is a device that replaces the original air tube plug.
After installing the regulator into Hatsan Flash airgun thanks to this quickfill with manometer you will be able to see pressure in airtube, because your manometer on airgun will show you regulated pressure. You can also monitor the pressure in airtube during filling more easily.
After installing the quick fill the air tube is immediately ready to fire.
Filling is possible from both sides so that it is always available at least one side of the filling hole at any angle air tube to the barrel.