Three-ply construction means this line of cookware offers the beauty of polished copper on the exterior with the superior heat distribution and retention of a heavy-gauge aluminum core. To complete the layers, the pan interior is made of finely brushed 18/10 stainless steel, as are the lid and stay-cool riveted handles. While the lid is oven-safe to 450 degrees F, the pan is broiler-safe uncovered to 550 degrees F, allowing a final browning of a casserole top after baking. Because of the high quality of Calphalon materials, lower heat settings and the use of very little butter or oil are recommended. Aerosol cooking sprays leave a residue that can cause food to stick and should be avoided. No pre-seasoning is required for the copper cookware line; just a good wash by hand in hot soapy water before first use, and thorough cleaning by hand after each subsequent use. Heat naturally changes the color of copper, resulting in an aged-look patina that many cooks love. However, occasional polishing with copper crème will keep the exterior looking shiny and bright. Non-sharp metal whisks, spatulas, and spoons may be used with the cookware, while knives and electric mixers should be avoided. Made in China, the Tri-Ply Copper is covered by Calphalon’s lifetime warranty. --Ann Bieri