Hard anodizing was first developed in 195B by the aerospace industry to produce a metal surface tough enough for space travel. The same technology is now used by us to make our Hard Anodized cookware. Hard anodized cookware is a lightweight product that is 30% harder than stainless steel. The aluminum that the cookware is made from goes through an electro-chemical in teraction process that makes the aluminum harder while still maintaining its light weight with wonderful properties for cooking. The Hard Anodized surface is non-toxic. non-staining and nan-reactive with foods It is thermal-efficient, heats fast and evenly and is not spoiled by high heat It is tough and durable, will not tarnish or corrode