Double-Sided Shutter Series Fan 1 cup oil with detachable design, more convenient cleaning and maintenance; 2 two mode first mode exhusust air second mode bring in fresh air 3 The series of products using advanced CFD CFD software to optimize the design, Air volume, low efficiency, low noise; 4 All the wind wheel balancing test and undergo a rigorous weight; 5 products located blinds to prevent outside air, mosquitoes into the room; 6 All products unified with ball bearings, copper coils, life of up to 5 years; 7 using hot reset protection, sealed housing, protection grade IP44; 8 high-quality start capacitor and three core sheathed cable, to the extreme harsh environments (-25 Degrees to 90 degrees) continuous operation; 9 thickening of the box housing, safer operation; 10. Provide OEM & ODM, one-year warranty.