Engel Cooler/Dry Box (3 Sizes)

I am sure this is a well-made box, but my question is about the stainless steel fittings.
While stainless steel resists corrosion, there’s still a world of difference between different grades of stainless steel. Anyone knows more detail on what kind of stainless steel they use for the hinges/latches?

I see Engel are expanding their product line. First they started with amp heads, and now coolers…