To entry the liquid fill port, you unscrew the highest cap. The threads are nice; it will come off effortlessly and screws on tight. The fill ports are large and simple to fill as well. Which tank retains 5ml of liquid, which is pretty good. The box mod is https://geekvapelegendmod36801.mdkblog.com/31666289/geekvape-legend-kit-things-to-know-before-you-buy