Rittal 3239124 TopTherm Filter Fan Unit Brand: Rittal. Part Number: 3239124. Rittal TopTherm Filter Fan Unit, 24 VDC, 0.23 A, 5.5 W Power, 46 dB Sound Level, 61.8 cfm Air Flow, Threaded/Surface Mounting, DC Motor, NEMA 3/3R/4/4X/12/IP54/IP55/IP56 Enclosure, 8 in W x 0.94 in D x 8 in H Dimensions. Additional Description: RTL -3239124 (O) FILTER FAN 62CFM 24 V DC NON-CANCELLABLE NON-RETURNABLE. Catalog Description: SK fan and filter units TopTherm, 105 m³/h, 24 V (DC), WHD: 204 x 204 x 24 mm..