Common Air Breathing Valve Design Mistakes and How Product Teams Can Avoid Them
https://siliconepartsblog.raidersfanteamshop.com/how-mini-optics-help-improve-light-control-in-space-limited-designs
Designing a small part can affect the whole product. A air breathing valve may look simple, but it has a real job to do. It must work with the cap, case, fluid, air path, or light path around it