The Air King RF-34S 7-5/8-Inch Replacement Charcoal Odor Filter is compatible with the Air King AV and DS Series. This filter provides duct free operation when used in combination with the RF35S and measures 7-5/8-inches by 7-5/8-inches. The Air King RF-34S 7-5/8-Inch Replacement Charcoal Odor Filter comes with a 1-year limited warranty. Air King offers a full line of industrial grade and commercial grade air circulating fan solutions to meet almost any need you might have. Whether your need is in industrial settings such as manufacturing plants and warehouses or more commercial setting such as offices, schools or hospitals - Air King has the perfect solution for you. Powerful motors that last for years and years are what Air King"s Air Circulators have come to been know as and we are not stopping now.