{HEAD ~ A threaded fastener} has {TAIL ~ a casing} enclosing at least three radially inwardly biased arcuate segments positioned to engage the threads of a bolt or hollow threaded member 
has
{ HEAD ~ A threaded fastener } has { TAIL ~ a casing } enclosing at least three radially inwardly biased arcuate segments positioned to engage the threads of a bolt or hollow threaded member
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH