Mini Air Purifier Compared with other , this USB plug-in air purifier is small in size and allows you to travel . Negative purification function: The air generator generates negative ions, which are combined with the dust of positive ions in the air and sink to the ground to avoid the danger of inhaling floating objects. And to achieve the removal of smoke, oil fume and other particulate matter. Effectively freshen the air and the quality of sleep. Low noise, environmental protection and health: This filterless air purifier allows you to work immediately without replacing expensive accessories, just plug it. Release 20 negative ions, so that harmful dust carried by positive ions in the air loses vitality. Easy to use, plug and play. Product name: USB air purifier Negative concentration: 20 pcs/cm Power plug type: USB Working principle: negative Noise: 36 (dB) Air volume of air purifier: 301-400 /hour Applicable area: 31 (inclusive)-40 (inclusive) Material:ABS+metal colour:Orange Package Contents: 1 x USB air purifier 1 x english manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.