I am specifying Stainless steel grade 304 for a product that will be used in harsh environment. I would like to passivate to improve corrosion protection. What "grade" of passivation should I specify on the engineering drawing? Are there actually grades of passivation? Just saying "Finish: Passivated" seems a bit general to me. There's lots of info out there, but I'm a bit confused. Can anyone offer some straightforward guidelines? Thanks in advance.