The ACF 528 will simultaneously cool up to Five avionics units. Operating on 28 Vdc the ACF 528 supply up to 20 cubic feet of cooling air per minute, helping maintain your avionics at a proper operating temperature. SANDIA Aerospace cooling fans use high quality, brush-less blower motors and or RunQuiet technology. The ACF 528 unit is FAA PMA and have passed stringent environmental testing to ensure years of reliable service.