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