510 battery - What metal is the outer jacket made of?

[X-Factor]

On a manual, 510 battery, what kind of metal is the outer jacket made of, and what kind of metal is the manual battery's connector tip made of? Thanks.

 

[cskent]

I believe the battery casing is stainless steel and the connector is brass, but some may be plated to a silver color. I may be wrong though.