All three fireboxes are made of powder-coated sheet metal 1.6 to 1.8 mm, featuring a grate for better combustion, a carrying handle and a 100 mm diameter pipe outlet. The air supply is adjustable in three stages on the door, with the smoke exhaust located on the rear side. Longer logs can be placed in the XL and XXL versions. The 'Firebox Replacement for XL' item can only be ordered together with a new smoker; it cannot be purchased separately. Further smoker parts can be found in the smoker accessories.