AIRLET 200 Fresh Air Inlet with White Exterior Grille (5&rdquo;-9&rdquo; Telescoping Sleeve) - Passive Filtered Fresh Air Inlet for Make Up Air Passive Self-Regulating, Filtered Fresh Air Inlet For Make Up Air Integrated Flow Regulating Damper Provides Draft Free Fresh Air Small 5 1/8" Round Opening Required See Specification Sheet For Details