Features: The Hooded Wall Vent Caps with Check Valves effectively prevents backflow, ensuring the efficient operation of your ventilation system. Produced from plastic, this vent Caps features a standard duct Interfaces design that is easy to install, robusts , and Corrosions resistant. Suitable for homeowner , building contractors, and HVAC Professional want reliable ventilation solution . Perfectly suited for residential and commercial building ventilation systems, especially in kitchen and bathroom exhaust applications. enhances your ventilation setups with this Multifunction vent Caps, designs to maintain airflows integrity across various architectural environment . Specifications: Material: plastic Diameter: about 75mm/110mm/160mm(optional) Package Includes: 1xWall Vent Caps note: Please allow 1 to 3cm error due to manual measurement, please make sure you do not mind before you bid, Due to the differences between different monitors, the picture may not reflect the actual colorful of the item.