This permits {HEAD ~ introduction} of {TAIL ~ a resilient cap}, which will secure the connecting sections within the hollow and allows otherwise trapped air to escape readily through the opening 
of
This permits { HEAD ~ introduction } of { TAIL ~ a resilient cap } , which will secure the connecting sections within the hollow and allows otherwise trapped air to escape readily through the opening
OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL 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