Rittal 3238124 TopTherm Filter Fan Unit Brand: Rittal. Part Number: 3238124. Rittal TopTherm Filter Fan Unit, 24 VDC, 0.24 A, 5.5 W Power, 46 dB Sound Level, 32.4 cfm Air Flow, Threaded/Surface Mounting, DC Motor, NEMA 3/3R/4/4X/12/IP54/IP56 Enclosure, 5.8 in W x 0.63 in D x 5.8 in H Dimensions. Additional Description: RTL -3238124 (O) FILTER FAN 32CFM 24 V DC. Catalog Description: SK fan and filter units TopTherm, 55 m³/h, 24 V (DC), WHD: 148.5 x 148.5 x 16 mm..