I've canoed and swam with INFI. They may not call it stainless, but for me it is.
In fact, I've canoes and rafted with stainless that did rust, where the INFI did not!
Once, with a bad, I swam with it multiple times while canoeing. It was hot, and wet, and sweaty, and I never dried it off. After the second day, I thought I saw a smudge of discoloration or rust right on the logo....
Then I wiped my thumb across it, ad it was gone.