This is for 1 Genuine replacement Water Panel Evaporator pad for Generalaire model humidifiers. #GA19.Water Panel Evaporators are the heart of your humidifier and the component which generates the important humidity to keep you comfortable during the heating season. The water panel slides into the scale control insert and the water distribution tray sits on top of it to evenly deliver water to the water panel. This water pad fits :Generalaire Elite series models 900 & 1000 Size: 12" x 9-7/8" x 1-1/2"