While four rollers are shown, {HEAD ~ the number} and size of the rollers may vary with the type and {TAIL ~ size} of fiber being treated 
vary with
While four rollers are shown , { HEAD ~ the number } and size of the rollers may vary with the type and { TAIL ~ size } of fiber being treated
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH