The SAFE 328 simultaneously cool up to three avionics units. The SAFE 328 supply up to 20 CFM (no load) of cooling air. Helping maintain your avionics at a proper operating temperature. The SAFE 328 provides an alert output should the blower RPM drop below a preset level. SANDIA Aerospace cooling fans use high quality, brushless blower motors and or RunQuiet technology. The SAFE 328 unit is FAA PMA and have passed stringent environmental testing to ensure years of reliable service.