**Four-Ply Stainless Steel with Copper Layer**

Four-ply stainless steel cookware material is based on the standard tri-ply structure, with an additional copper layer added to the outside. The copper layer is usually around **0.3 mm to 0.5 mm** thick, giving the cookware a premium appearance and improving its high-end market positioning.

Because copper is not magnetic, cookware with a full copper exterior cannot work directly on induction cookers. To make the cookware induction-compatible, the copper on the bottom can be polished away to expose the **430 magnetic stainless steel layer**, or an additional **430 stainless steel induction plate** can be pressed onto the bottom.

The copper exterior gives the cookware a beautiful and luxurious look, but it also requires proper care. Copper can oxidize in the air and gradually develop a greenish patina over time. If customers want to keep the copper surface bright and shiny, the cookware should be wiped dry after washing and maintained regularly with suitable copper cleaner or rust-removing solution.

This four-ply stainless steel copper composite material is suitable for premium cookware brands, high-end kitchenware collections, copper cookware sets, professional cookware lines, and customers who want both stainless steel performance and a classic copper appearance.