With this humidity meter, we will all be using our lash glue the pro- way.
The main ingredient in your lash glue is cyanoacrylate.
The purpose of cyanoacrylate in your glue is to make sure  the lash glue dries quickly and holds the lash extensions in place for several weeks.
This cyanoacrylate needs an activator to start curing and this activator is called “moisture”.
With the presence of moisture, your lash glue will start to cure and create a bond hold between the natural lash and the lash extension.
Humidity means “the amount of water in the atmosphere “. 
This will affect how your glue works as most lash glue requires specific humidity level for their glue to function properly at its best.
For optimal performance of lash extension glue, your room humidity levels must be between 45-60%.
If you leave in a dry environment and your humidity level doesn’t fall within this range, you must try to keep your room humidity level at 45-60% as much as possible. 
Using spray mist and humidifiers can help increase the moisture in the environment to create optimal performance of your glue.
You don’t want your client calling you about their lash falling off the next day.
This device is called humidity meter which help you keep track of the humidity level in your lash room. 
When humidity is higher than 60%, the cyanoacrylate in your glue will be ‘overly activated’ by too much moisture in the air, which means that the lash adhesive will cure and dry much faster than usual causing the lash and extension not binding properly.
If the room humidity is extremely high (over 70%), the cyanoacrylate stops working and your glue won’t cure causing the lashes to fall off the next day.