The products filled in airless dispensers hence are hermetically protected against bacterial and material contaminations of the external atmosphere. Thus airless dispensers are a practical and absolutely hygienic solution. In comparison with jars or tubes, however, it is more difficult to assess the remaining quantity with the result that dispensers can be empty all of a sudden.
Concerning white airless dispensers, there is a simple trick for assessing the remaining quantity. Just use a light source on the bottom side as described in the following:
- Turn on flashlight mode on smartphone
- Put smartphone on the table with light source up
- Place airless dispenser on light source
The following figure shows airless dispensers with different filling levels:
Figure: Checking the remaining quantity using a smartphone
The empty space appears as well-lit area and the double bottom area is a dimly lit grey area while the remaining quantity remains dark.