{HEAD ~ A fan} is mounted to the housing and is operably disposed, preferably, within the plenum to draw air from the plenum and to exhaust the air outside of {TAIL ~ the housing} 
{ HEAD ~ A fan } is mounted to the housing and is operably disposed , preferably , within the plenum to draw air from the plenum and to exhaust the air outside of { TAIL ~ the housing }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL