How to choose the right size Easybreath mask

Our Easybreath Mask comes in 3 different sizes:
XS: for children aged 3-10
S-M: children over 10 years of age and female adults
M-L: adult men (typically)
We have a super easy returns policy, so if you purchase a size and it doesn't fit, you will always be able to return it and purchase a new size.