1、[Good Versatility] With special reducing ring design, this check valve is suitable for most range hoods, suitable for pipe diameter of 80mm to 110mm. 2、[Automatic Open and Close] Automatically open and exhaust smoke through the exhaust wind, and close quickly through gravity and strong spring. 3、[Anti Odor and Mosquitoes] The check valve can firmly block outdoor odors and mosquitoes, keep your kitchen environment refreshing and clean. 4、[Good Sealing] Using silicone sealing ring and backboard sealing strip, closely fit the range hood and wall, leaving no gaps and no smoke leakage. 5、[Easy to Install] With upgrade design, the range hood check valve can be installed easily and quickly in simple steps.