TileIntake®Model IV-9, TileIntake® 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.Model IV-9, TileIntake® 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.Model IV-9, TileIntake® - Installation 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.Model IV-9, TileIntake® - Installation 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.Model IV-9, TileIntake® - Installation 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.Model IV-9, TileIntake® - Installation 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.Model IV-9, TileIntake® - Installation 4' tile intake stick vent, 9 square inches of Net Free Area per linear foot.