Fits head sizes 21.7 to 22.0 inches (55 to 56 cm.) Pro-tec s exclusive Lo-Pro 2-stage foam skate helmets are what put us in the books by offering maximum comfort and a light airy feel. Outlawed in some states and revered in others. Not Certified: (These helmets use 2-stage foam that does not meet certification standards and should only be used for skating)