Calphalon Tri-Ply Stainless Steel 13-Piece Cookware Set 1767951Calphalon Tri Ply Stainless Steel Cookware Three layers deliver even, consistent heating. Classically styled with a polished stainless steel exterior and a satin finished interior, Calphalon Tri Ply Stainless Steel cookware is designed with three layers to ensure even, consistent heating. A heavy gauge, aluminum core surrounded by two layers of stainless steel provides excellent heat conduction for browning and enhanced control of the cooking process.