Magnetic hygrometer holder.
You can attach it anywhere you like, such as a glass case or spool box.
No drilling required.
Requires 6x3mm 6 magnets.
Once printing is complete, insert the magnet.
Place the magnets so they are facing each other. Attention to the orientation of the magnet.
Push in the square hygrometer.
Install it so that it sandwiches a glass plate, etc.
When installing on glass, be careful not to damage the glass.