Stopper 26 further is provided with {HEAD ~ a threaded opening} 29 for {TAIL ~ a nut} 30 
for
Stopper 26 further is provided with { HEAD ~ a threaded opening } 29 for { TAIL ~ a nut } 30
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH