Start with a test, not a guess
The fastest way to find your size is to try several. That's why our starter pack exists: four sizes in two styles. Give each candidate one evening of thirty minutes before bed and, if it feels fine, one full night.
Take the medium first. Most adult noses land on medium or large.
Signs you need a bigger size
The vent slides forward when you breathe out, falls out on the pillow, or you can't feel any difference in airflow. Move up one size and try again.
Signs you need a smaller size
You feel pressure inside the nostril after ten minutes, the skin is red in the morning, or it's hard to get in without forcing. Go down one size. Never push a vent past the point of slight resistance.
Soft or firm?
Soft silicone vents bend with your nostril. They're more forgiving and the easiest to get used to. Hard cones in polypropylene keep their shape: the right call if your nasal walls are soft and tend to collapse a vent overnight.
Soft-cone dilators sit between the two, with a tapered tip that goes in easily and a firmer base that holds.
Once you know
Order the 12-pack in your size and style. It costs less per vent and comes with its own travel case. Rinse every morning, swap for a fresh pair every few weeks.