FK-14 build vertical Louver Texas Feiyu Seiko Sales Hotline: 13969272212 
 Usually rely on the outlet of the venetian weight and natural sag, cut off from the exchange of indoor and outdoor air, when the indoor air pressure is greater than the outdoor air pressure, air will blow open the louvers out the exhaust, on the contrary the indoor air pressure is less than the outdoor air pressure, air can not the reverse flow of indoor, one-way only to return to the role of the outlet. 
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