{HEAD ~ The filter} 11 is coaxially housed in {TAIL ~ an outer cylindrical casing} 4 with a gap 14 provided within the casing and is retained by a pair of front and rear shielding plates 17 and 18 
is coaxially housed in
{ HEAD ~ The filter } 11 is coaxially housed in { TAIL ~ an outer cylindrical casing } 4 with a gap 14 provided within the casing and is retained by a pair of front and rear shielding plates 17 and 18
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL REL TAIL 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 OTH OTH OTH