1、Automatic Opening: Special reducer loop design, suitable for most hoods, just open the check valve, through the exhaust wind, automatically open the smoke exhaust. 2、Firmly Block: When the check valve closes, it closes by gravity and its own spring, firmly blocking the outdoor odor and bugs. 3、Slant Gravity Sealing: The check valve has a slant gravity sealing for grease and smoke not to back up, stainless steel strong spring, fast sealing after exhausting smoke, silicone sealing ring. 4、Close Fit: Check valve can be a close fit, leaving no gaps, back plate sealing strip, stick to the wall without leakage. 5、Quick Installation: Check valve with level design, installation in one step, the main body and fixed seating can be detached and separated, installation is faster and more convenient.