{HEAD ~ A plurality} of rollers are fixably and independently mounted in {TAIL ~ each} of said channel members 
are independently mounted in
{ HEAD ~ A plurality } of rollers are fixably and independently mounted in { TAIL ~ each } of said channel members
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH