This Burnham Commercial Vent Connector is a crucial component designed to facilitate the connection between different sizes of venting systems. Specifically, it enables a transition from a 3-inch diameter vent to a 4-inch diameter vent. The model, identified as G3, is made from high-quality, durable materials that ensure longevity and optimal performance. This product is typically used in commercial heating systems where it plays an essential role in maintaining the efficiency and safety of the system by ensuring proper exhaust gas flow. It's important to note that this vent connector should be installed by a professional to ensure correct fitting and adherence to safety standards.