Copper
offers the ultimate in underground durability. Archeological
digs often recover items made of pure copper in superb condition
after 8,000 years.
Stainless
steel is an alloy of iron, carbon, chromium, and nickel. The
stainless steel used in Clark vaults is a premium grade alloy
with high chromium and nickel content. The Gateway Arch in St.
Louis is made of the same high quality alloy used to manufacture
stainless Clark vaults. Many common kitchen accessories are
available in stainless steel such as cookware, flatware and
sinks.