{HEAD ~ The pressure supply conduit communicates} with an external source of air, or {TAIL ~ a detachable cartridge} of a biologically compatible compressed gas 
{ HEAD ~ The pressure supply conduit communicates } with an external source of air , or { TAIL ~ a detachable cartridge } of a biologically compatible compressed gas
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH