{HEAD ~ Cartridge} 24 preferably includes {TAIL ~ a lip seal} that prevents ingress of dust into the cartridge 
{ HEAD ~ Cartridge } 24 preferably includes { TAIL ~ a lip seal } that prevents ingress of dust into the cartridge
HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH