{TAIL ~ The driving devices} act into the ring gap, and {HEAD ~ each} of the driving devices has a separate drive 
{ TAIL ~ The driving devices } act into the ring gap , and { HEAD ~ each } of the driving devices has a separate drive
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH