Redesigned, five speed, custom fit blower for efficient, quiet and comfortable operation;Multi-firing technology;Resized fan switch eliminates nuisance cycling;Classic 18" width dimension for tight replacement jobs;MA 100, MA 200, and CB 200 bases for versatility in applications;Drum/Tubular heat exchanger assures long life;Disposable filter (16x25x1) in the door;New plunger-style door switch;New tilt out door with more louvers for better airflow;Insulated cabinet;Metal pawl latch firmly secures door to furnace cabinet