Specifications: Diameter without rubber ring: 16mm Diameter with rubber ring: 20mm. Cable length: 70mm Colour: white. Control voltage: DC 3-12V. Power: 1.5W Lifetime: > 3000 hours. A-Tomization of Amout: 15 ~ 450 ml/hour. Note: 20mm diameter for pastic ring size. Contents: 5 pcs 16mm ultrasonic humidifier accessories.