providing a first roller adapted to receive {HEAD ~ the additive material} within a plurality of {TAIL ~ spaced apart pockets} located on its roll face 
providing a first roller adapted to receive { HEAD ~ the additive material } within a plurality of { TAIL ~ spaced apart pockets } located on its roll face
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH