The cover can be formed of a polymer blend including {HEAD ~ a polyurethane composition} and {TAIL ~ the core} can include a polybutadiene composition 
The cover can be formed of a polymer blend including { HEAD ~ a polyurethane composition } and { TAIL ~ the core } can include a polybutadiene composition
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH