This GeneralAire replacement humidifier pad is for humidifier models 570, 570A, 570M, 570X and 570XM. Also known as water panel evaporators, media filters or evaporator pads, this is the component which generates humidity to keep you comfortable. When warm air from your furnace passes through the vapor pad it absorbs the water which evaporates into your home creating humidity. The humidifier pad needs to be replaced once water deposits have built up preventing warm air from passing through. The actual size of this media filter is 10″ L x 9-1/2″ W x 1-7/16 D.