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