{TAIL ~ means} for discharging the carbon dioxide from {HEAD ~ the canister} and into the housing 
{ TAIL ~ means } for discharging the carbon dioxide from { HEAD ~ the canister } and into the housing
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH