The inner core can be comprised of cork, {TAIL ~ kapok}, {HEAD ~ rubber} or a blend of thermoplastic polymers and copolymers 
The inner core can be comprised of cork , { TAIL ~ kapok } , { HEAD ~ rubber } or a blend of thermoplastic polymers and copolymers
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH