This BDP P1103545 Compatible Humidifier Water Panel Filter is a furnace humidifier evaporator pad that is constructed of honeycomb filtration that helps to trap waterborne mineral contaminants and prevents them from entering the indoor air of your home. This BDP water panel filter measures approximately 10" x 13 1/4" x 1 1/2". Replace your humidifier filter once every 6 months or more frequently in hard water areas for optimum performance.