All American Tackle guides are 316 alloy stainless frames that I have never seen corrode, as some other brands claiming to be 316 alloy will do.
Aside from the Halide ring models, all other guides have zirconia rings (nanolite, duralite).
Zirconia is what synthetic diamonds are normally built from.
Low and mid range Fuji guides use aluminum oxide rings, which is what sandpaper is made with. These grade Fuji guides are usually 304 or 308 stainless alloy frames, which is not as strong as the 316 and far less corrosion resistant.
You dont need ultra high quality guides in most situations, but in the salt, corrosion resistance has to be a concern.