Also shown are {HEAD ~ the exterior surface} 23 of {TAIL ~ the top portion} 7 and the exterior surface 24 of the bottom portion of the housing 
Also shown are { HEAD ~ the exterior surface } 23 of { TAIL ~ the top portion } 7 and the exterior surface 24 of the bottom portion of the housing
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH