This is the gasket that is sandwiched between the hopper and the grill barrel. It serves to cushion the vibrations caused by the pellet grill operating, keeps smoke from leaking through the opening of the barrel where you insert the auger assembly through and a heat barrier to the grill hopper. Outer Dimensions: Length 6 3/4" x Width 5 1/8" Inner Dimensions: Length 5 1/4" x Width 4" Compatible Pit Boss Models: 1000 Traditions 2, 1000 Traditions, 1000NC Nascar Edition, 1000SC, 1000SC2, 1000T4, 340, 440 Deluxe, 440D2, 440NC Nascar Edition 440TG1, 456D3, Classic, 700D, 700FB, 700NC Nascar, Edition, 700S, 700SC, 700T1, 820 Deluxe, 820D3, 820FB, 820FBC, 820S, 820SC, 820XL, Austin XL m KC Combo Platinum, Navigator 1150, Navigator 550, Navigator 700, Navigator 850, Navigator Combo, Pro Series 1100 Combo, Pro Series 1100-PS1 (Lowes), Pro Series 820-PS1 (Lowes), Pro Series II 1100 Combo, Pro Series II 1150PS2, Pro Series II 600, Pro Series II 850PS2, Ranch Hand, Rancher, Rancher XL, Sportsman 1000, Sportsman 1100, Sportsman 500, Sportsman 820, Sportsman Combo, and Tailgater USA-Based Seller With 7 Days-a-Week Customer Support. This is the gasket that is sandwiched between the hopper and the grill barrel. It serves to cushion the vibrations caused by the pellet grill operating, keeps smoke from leaking through the opening of the barrel where you insert the auger assembly through and a heat barrier to the grill hopper.