The housing is further formed with a cylindrical cavity, and {HEAD ~ a manually rotatable hollow cylinder} is received within {TAIL ~ the cylindrical cavity} 
is received within
The housing is further formed with a cylindrical cavity , and { HEAD ~ a manually rotatable hollow cylinder } is received within { TAIL ~ the cylindrical cavity }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL