[SIZE S].

It is one size smaller than the "small" size of disposable masks generally sold.

This is for children, or those with fairly small faces that have plenty of room in the "small" size of commonly sold disposable masks.

[SIZE M]

It is sized for women, or especially for men with smaller faces.

The "small" size of disposable masks sold in general is just right.
The size of the mask is larger than the disposable mask mentioned above, but there is a large hollow in the side.
In any of the above cases, we recommend the size M.

In the case of an employee who was using a disposable mask "small for women" size (14.5 cm wide and 9.5 cm long), this Primefect Mask was just the right size for a size M, adjusted with a strap.

[Size L]

This is the size of a generally available disposable mask for adults.

[When you're not sure which size to take]
If you're not sure which one to choose, we recommend the larger one.

Even if it's a bit large, you can adjust the straps to fit your face and cover it more tightly over a wider area.