Assembled Product Length: 10" Coverage: N/A Volume Capacity: N/A Assembled Product Height: 1.5" Assembled Product Width: 9.5" . The humidifier spreads water over the humidifier pad, warm air blows over the water soaked area and vapour is generated As the vapour circulates through the house, the relative humidity rises For use on all the HE220/HE225 humidifiers Can be used for Aprilaire models 110, 120, 220, 550 and 558 Replaced model #HC22-A1007 HOUSE AIR CHANGES AREA (Up To) DESCRIPTION PER HOUR sq. ft. sq. mtr. Loose 2 750 70 Average 1 1,500 140 Tight 1/2 3,000 280