Williams Furnace Company 2901 Blower Accessory For use with models 2509821, 2509821, 3509821, 3509822 , 5009821 and 5009822. Two blowers may be used on models 5009821 and 5009822 (one on each side of the furnace) Moves air at up to 100 CFM for effective use Grille painted soft white to match the furnace casing