Avoid settling for a less-than-perfect alloy. All our stainless steels are Marine Grade 316 Stainless STEEL (A4). Our 316SS fasteners are far more corrosion resistant than their 304SS (A2) or 18-8 counterparts due to the higher nickel content and addtion of molybdenum in the alloy. Upgrade your fasteners to 316SS instead of 304SS if you intend to use them in a marine setting or an environment that is otherwise corrosive.
The big box stores sell inferior stainless metals simply labeled as “stainless”. They do not name the alloy. The fasteners sold in big box stores are most likely not the same 316SS alloy that is required for marine fasteners. Fair Wind Fasteners deals only in alloys and fasteners which we ourselves would use. 316 Stainless Fasteners