... big or small fog by rotating the switch to control Description for Ultrasonic humidifier : 1,Energy-saving circuitry devising; 2,From left ... ,The big or small fog by rotating the switch to control, convenient operation; 4,Max fog can reach 300ML / H; 5 ... ; 6, Automatic water cut-off protection device; 2012 Hot sale ultrasonic cool mist humidifier for home, office and car