Selkirk RV 4" x 4-3/4" x 9-1/2" Gas Vent Collar serves both functional and aesthetic purposes within a gas venting system, especially one using Type B gas vents. This collar provides a finished and decorative look to the vent installation, ensuring it appears clean and well-finished. Beyond its visual appeal, it acts as a firestop, helping to prevent the spread of fire through openings in floors, ceilings, and walls where the gas vent passes. The collar is designed with a specific dimension, including a C measurement of 2-3/8". The sizing refers to the inside diameter of the pipe or fitting, while the outside diameter of RV pipes is typically about 1/2" larger. Overall, this gas vent collar enhances both the safety and appearance of the venting system. Model Number: 104460