A room air filter apparatus includes {HEAD ~ a multi sided housing} having longitudinally spaced first and second ends, a plurality of sides between the first and second ends, and a plenum inside {TAIL ~ the housing} 
A room air filter apparatus includes { HEAD ~ a multi sided housing } having longitudinally spaced first and second ends , a plurality of sides between the first and second ends , and a plenum inside { TAIL ~ the housing }
OTH OTH OTH OTH OTH OTH HEAD HEAD 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 TAIL TAIL TAIL TAIL TAIL TAIL