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