The belts tend to center themselves toward {HEAD ~ the high points} of the crowns, but are narrow enough to leave edges of {TAIL ~ transported envelopes} free for registration 
The belts tend to center themselves toward { HEAD ~ the high points } of the crowns , but are narrow enough to leave edges of { TAIL ~ transported envelopes } free for registration
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH