PRESSURE RELIEF PORTTHE FUNCTION OF THIS VENTILATOR IS TO KEEP THE INSIDE AND OUTSIDE PRESSURE TO BE BALANCE ABLE,EVEN THE INSIDE TEMPERATURE IS UBDER 0'C,AND ENSURE OPENING OR CLOSING THE DOOR SMOUTHLY WITH A  STAINLESWS STEEL FILATING NET,WHICH PREVENT THE INSECT FROM ENTERING AC 200V OR 110V ARE ON YOUR OPTION
        LONG TERM IS ONE OF THE LEADING COMPANY SPECIALIZED IN HVAC AND LOW VOLTAGE AREA. WITH OUR PROFESSIONAL TEAM, WE HAVE DEVELOPED VARIES SERIES OF PRODUCT COMPLIED WITH ISO AND INTERNATIONAL STANDARD (UPC,NSF,UL). OUR PRINCIPLE IS: QUALITY ENSURES SURVIVAL.
WITH TIME GOES BY, OUR PRODUCT IS POPULAR ALL OVER THE WORLD. FURTHERMORE, WE HAVE ALREADY SET UP SOLE AGENT IN MANY COUNTRIES IN ORDER TO BETTER MEET CUSTOMERS' RAPID CHANGING REQUIREMENTS.

     WE BELIEVE THAT YOU CAN FIND WHAT YOU NEED FROM OUR WEBSITE, IT IS YOUR WISE CHOICE TO CONTACT US. WARMLY WELCOME YOU TO WRITE MAIL TO US DIRECTLY.