2 Humidifier Filters for Aprilaire 35-models 560 560a 568 600 600a &700a Premium aftermarket humidifier filters (water panel pad) designed to fit Aprilaire Humidifier Models 350, 360, 560, 560A, 568, 600, 600A, 600M, 700, 700A, 700M, 760, 760A, 768. Compare To Aprilaire 35 Water Panel Part Filter Panel has a black mark indicating which is the top of the panel when reinstalling into humidifier. If installed upside down water will run off the panel. The pad is constructed of an expanded aluminum honeycomb mesh that is dipped in a clay coating. This coating is able to absorb and hold water. Warm, dry air is forced through the wet pad to introduce water vapor into the home. Approximate dimensions: 10" x 13" x 1 3/4" Bulk packed For optimal performance, we recommend to change your water panel every 3 to 6 months, or as needed