LEVOIT Classic300 Ultrasonic Top Fill Humidifier, Extra Large 6L Tank Last 60-Hour - Super Quiet, Easy to Use and Clean, 360° Rotation Nozzle, Simple Knob Control, Handle, Auto Shut Off, Gray

Troubleshooting:What is the water filter sponge?Why to use: Capture and filter fine impurities and particles, to improve humidifying efficiency in a healthier way.When to change: Generally lasts 1 month depending on hardness of water.Where to buy: Please search B09ZY9N6PD or LEVOIT 10-Pack Humidifier Replacement Filters on Amazon.Note: Distilled/ purified water is preferred for your health. Specifications:Product Dimensions: ‎9.7 x 8.1 x 13.4 in / 24.5 x 20.5 x 34 cmWhisper-Quiet Operation: ≤ 30dBEffective Range: 215-505 ft² / 20-47 m²Material: BPA free, suitable for babies and adults.