Features Fine Atomizing: Ensuring fine and even atomization effect under 1.7MHz frequency, high in efficiency and stable in working. Practical Uses: Allows for extensive application on humidifier, dust collector, cleaner, atomizer and so on, very useful. Reliable Works: Adopting premium ceramic material, not easy to break, and has a long service life up to 3,500 hours as well. 10Pcs in Total: There are 10pcs ceramic disc in the set, and the large quantity simplifies the replacement of old parts. Easy to Install: Use the key tool to turn the winding ring counterclockwise to remove the old one. Then put on a new disc and tighten the upper chain ring clockwise. Specification: Item Type: Ultrasonic Mist Maker Model: RM0920 Product Size: Approx. 20mm / 0.79in Service Life: 3500h Frequency: 1.7MHz Application: For humidifier, dust collector, sterilizer, atomizer.  Package List: 10 x Ultrasonic Mist Maker 1 x Iron Plate Note: Note the different sides of the ceramic plate. When installing a new ceramic plate, you need to place the ceramic plate with the white side facing up. Package List 10 x Ultrasonic Mist Maker 1 x Iron Plate