The primary difference between 18-8/304 and 316 stainless steel nuts is their corrosion resistance. Both are highly durable, but 316 stainless steel contains a higher percentage of molybdenum, making it more resistant to rust and pitting, especially in saltwater environments. While 18-8/304 stainless steel is adequate for freshwater use, 316 stainless steel is the better choice for marine applications where prolonged exposure to saltwater can cause faster degradation.