In {TAIL ~ an alternative embodiment}, the core has {HEAD ~ a compression} of 60 or less 
In { TAIL ~ an alternative embodiment } , the core has { HEAD ~ a compression } of 60 or less
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH