Round Fiberglass Gasket For All Traeger Pellet Grills That Has A Chimney Inner Diameter: 3", Outer Diameter: 5-1/2" Easy Installation. Replacing A Worn Out Chimney Gasket Will Improve Heat & Smoke Flow In Your Pellet Grill Barrel & Make Your Grilling More Efficient USA-Based Seller With 7 Days-a-Week Customer Support. Replacement flue pipe gasket compatible with all Traeger Pellet Grills that have a chimney stack. The inner diameter is 3" and the outer diameter is 5.5". Replacing this gasket will ensure a better heat and smoke flow throughout your pellet grill barrel and ensure a more efficient grilling experience.