Selkirk RV 3" x 3-3/4" x 8-1/2" Gas Vent Collar is designed to enhance both the functionality and appearance of your gas venting system, especially those using Type B gas vents. This collar a clean, finished look to your vent installation, ensuring it appears neat and well-maintained. Beyond aesthetics, it also acts as a firestop, helping to prevent fire from spreading through openings in floors, ceilings, and walls where the gas vent passes. The collar measures with a C dimension of 2-3/8", referring to the inside diameter of the pipe or fitting, while the outside diameter of RV pipes is typically about 1/2" larger. This product improves both the safety and the visual appeal of your gas venting setup. Model Number: 103460