the head is a starting point for the entire sizing procedure.
Due to varying shapes, heads that are apparently the same size
when measured by a tape may not necessarily fit the same size
metal tape measure, or a cloth tape may be used to make your
circumference of the head should be measured at a point
approximately one inch above the eyebrows in front, and at a
point in the back of the head that results in the largest
possible measurement. Take several measurements, to make sure
you have the largest one.
PLEASE NOTE THAT THIS IS A ROUGH GUIDE AND NOT EXACT. THE SHAPE
OF YOUR HEAD IS AS IMPORTANT AS THE MEASUREMENT WHICH MAY AFFECT