The York S1-373-19804-651 4-Cell Heat Exchanger with Gaskets is a durable replacement component designed to efficiently transfer heat within compatible York gas furnaces and residential HVAC heating systems. It works by safely transferring heat from the combustion process to the circulating air while keeping combustion gases separated, ensuring safe and efficient operation. Supplied w... https://www.partshnc.com/york-s1-373-19804-651-4cell-heat-exchanger