Fits GeneralAire power humidifier (drain type) models SL-16 series, 709 series, 990 series, 1040 series, 1042 series, and 1137 series. * GeneralAire humidifier filters (evaporator pads). * Measures approximately 9-3/4" x 12-1/4" x 1-1/2". * Evaporator pad is coated with a non-soluble wetting agent to increase humidifier efficiency. Excess coating may shake off before first use.