{HEAD ~ The igniter} 2 wherein said gap filler has {TAIL ~ a relative permeability} of not greater than 15 
{ HEAD ~ The igniter } 2 wherein said gap filler has { TAIL ~ a relative permeability } of not greater than 15
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH