Along with all the improvements to the mask, we've improved our sizing and fitting as well!
 General Guidelines For Sizing:
 "Small" - Persons under 125 lbs.
 "Medium/Large/XL" - Fits most people.
 "XXL" - Persons 275+ lbs.
 Existing RZ Mask User - Follow These Instructions:
 If you wear either Medium, Large or XL in any of our other mask models, you will wear a "Medium/Large/XL" size M3 Mask.
 If our Medium size was too big for you, you would wear a "Small" M3 Mask. If our XL size was too small for you, you would wear an "XXL" M3 Mask.
 **Please note that these are general guidelines and everyone's face is different. We offer hassle free returns and exchanges to ensure everyone receives the correct size mask.