The Aluna Device:
Aluna is a single user device. This means that the spirometer is calibrated for use by only one individual. A second person using the same spirometer would result in mixed data.
As a matter of hygiene, Aluna should not be shared between users. You would not share a toothbrush, and so you should not share a mouthpiece.
The Aluna App:
If you have more than one Aluna user in your household, you can track all pilots and their results in a single instance of the Aluna app. Read about how to add pilots in this article.