1. Compact dimensions design. 2. High efficiency, energy saving design by EC technology. EC axial fan size 500mmDetail description:1. Wide range of accessories for selection, including guard grille, inlet ring, impeller, rotor.2. Number of blades: 53. Direction of rotation: CCW, seen on rotor.4. Control input: 0~10VDC/PWM5. Protection: locked-rotor protection, soft-start, thermal protector.6. ...