You need to search about 'pleats'.
These are sewn in folds that reduce the perimeter and get rid of ripples.
When a system is too large for the head, the ripples can appear anywhere, at the front, side or back.
If you send in an accurate template with a custom order, the system is made to that shape, circumference and contours, and the fit eliminates ripples.
http://forum.toplace.com/search.php?acti...order=desc