To size yourself, it would require a device called a faciometer which is not very common. ?
Size 2 (medium) fits 95% of the population, so if you're an average size person, we would suggest size 2.? For smaller than average people who weigh 130lb or less, with thin faces, we would suggest size 1 (small). For users over 250 lbs and wide faces, go with large.
We have a free exchange program in case it doesn't fit, so rest assured that no matter what we'll make sure you get the right size. You will know the size is right if you do a negative pressure test (blocking the inhalation valve and taking a deep breath), and the mask seals tightly to your face.
Please Note: Filters are NOT included. Please make sure to choose the appropriate size on the drop-down menu.