Butterfly Check Valve Draft BLOCKERS Vent Flue Check Valve Backdraft Damper for

【BACKDRAFT DAMPER】: Square air duct connector with Check valve, made of durable material, resistant to oil and heat. 1 Backdraft Damper. 【EASY TO INSTALL】 : Wall mount air duct check valve, with duct adapter rings, can be perfectly match with soft and hard duct.

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