wherein {TAIL ~ the pair} of {HEAD ~ female slots} project inward away from the outer surface of the exterior housing along a constant angle from the outer surface of the exterior housing to an inner end of the slots 
wherein { TAIL ~ the pair } of { HEAD ~ female slots } project inward away from the outer surface of the exterior housing along a constant angle from the outer surface of the exterior housing to an inner end of the slots
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH