the heat exchanger 170 from the fins 126 this configuration therefore assists in the collection of grease particles in addition the airflow path creates turbulence that increases exposure time of the air with the heat exchanger 170 accordingly one embodiment of the present invention allows no direct airflow path through the filter assembly 110 or a majority of the airflow therethrough is not direct indeed as shown in fig3 the fins and baffles reverse airflow to a path oriented about 45 180 u00b0 from the direction of flow at the upstream side of the filter unit one or more tortuous airflow paths 150 are created thereby creating turbulent flow that exposes the heat exchanger 170 to heated air for a sufficient amount of time to allow for adequate heat exchange to a fluid flowing through the heat exchanger 170 one or more retainer tabs 128 are formed on at least one of the lateral side members 120 of the base 112 the retainer tabs 128 may be on two opposing lateral side members 120 a retainer tab 128 is extruded from the lateral side number 120 so as to provide a resiliently deflectable retaining member also provided on the base 112 is at least one handle 130 which may be formed in a variety of ways the handles 130 are provided in opposing positions on the filter unit 100 to allow for balanced insertion and removal of the filter unit 100 from an exhaust system the handles 130 are full or partially wire loop handles that are suspended.