supplying {HEAD ~ the additive material} to within the pockets on the roll face of {TAIL ~ the first roller} 
supplying { HEAD ~ the additive material } to within the pockets on the roll face of { TAIL ~ the first roller }
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL