Tips on how to fill this container?
After you've filled the container, you press the roller ball down until it snaps into place.
However, you need to be aware of two things:
Firstly, when handling the roller ball you need to handle it with sterile gloves or a clean plastic bag acting as a glove - do not touch it with your bare hands unless you're making one for your own use;
Secondly, once the roller ball is snapped into place you cannot remove it again so make sure you have all of the ingredients in the container before snapping it into place.
If you fill it with a product containing too high a percentage of essential oils in it (over 15% approx.) then the roller ball may start disintegrating.
Liquid products are best filled with a spouted beaker or measuring cylinder.
Another good choice is to fit a small funnel into the neck of the bottle and pour in your product that way.