In the second operational position, the second register provides for residential used air intake in the second chamber and {HEAD ~ expulsion} of the air leaving {TAIL ~ this second chamber} into the atmosphere 
In the second operational position , the second register provides for residential used air intake in the second chamber and { HEAD ~ expulsion } of the air leaving { TAIL ~ this second chamber } into the atmosphere
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH