Every person's nose is different with nostril sizes that range from tiny to huge like mine. My wife, Amy, says "You could drive a truck up those nostrils!!!" So the Extra Large works for me. How about you?

Our experience is most women will find the medium works well and most men the large but with five sizes from Extra Small to Extra Large, how do you narrow it down?

We discovered an interesting fact. The size of the end of your thumb is approximately the size of your nostril. It's weird, I know. Try it out. Stick your thumb into your nose and you will likely find it just fits, ask me how I know! If that grosses you out then just trust me, your thumb measurement is close enough.

On our website, we have this cool graphic that shows how to measure your thumb and the corresponding sized filter.

As always, if they don’t fit right after ordering just email me at info@o2armor.com and I’ll get you the proper size.  Hope that clears it up. 

Breathe well, Live well,

Cliff Day