Breather hole
The chartplotter has a breather hole located on the bottom of the unit next to the product label.
Breather hole
Important
When the chartplotter is being surface or flush mounted the breather hole must not become blocked by sealant or other materials used to seal around the edge of the chartplotter.
Breather hole locations

Axiom Pro 16 / Axiom 2 Pro 16 breather hole location.
Axiom Pro 9 and 12 / Axiom 2 Pro 9 and 12 breather hole location.