{TAIL ~ Left and right valves} are provided in a lower surface of {HEAD ~ the cover} on opposite sides of the seal between the partition and the cover 
{ TAIL ~ Left and right valves } are provided in a lower surface of { HEAD ~ the cover } on opposite sides of the seal between the partition and the cover
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH