100% Stainless Steel.Patented 2-Piece design.24 gauge hood.20 gauge one-piece base with 8" high built-in screening. 5/8" mesh is standard that conforms to California codes.Superior animal proof oval hole mesh prevents creosote build up.Will fit flues sizes from: 8.5" x 16" to 11" x 18.5".Lifetime Warranty.Made in the USA.