Noise: 30 db Working principle: anion Applicable area: less than 10㎡ Product category: air purifier Control mode: mechanical Rated frequency :50HZ Function: remove formaldehyde Color: square [gray], square [white], bear [blue], bear [pink] Air volume of air purifier :50 m³ / h Square size :1.5*5*5cm Filter type: composite filter Product size of bear :1.5*5.7*4.5cm Power supply :USB Product includes: 1* Air Purifier, 1* charging cable, 1* user manual Note: The light socket and the different screens can cause the color of the item in the image to be a little different from the actual one. The allowed measurement error is +/- 1-3 cm.