The Liberty V9 0.5mL attachment from Itsuwa features a wickless ceramic element embedded within a removable center post. This unique design allows you to easily refill the V9 quickly and easily, while minimizing waste. To use, simply unscrew the center post from the top, add your essential oil up to the fill line, but do not fill past it or it will overflow when tightened. Once filled to the line, carefully place the top part back in and screw on tightly. That's it, you're ready to use! Next, simply adjust the top airflow ring while in use to fine tune aroma output to your liking. To refill anytime, just unscrew the center post, fill back to the line, and replace.