We only use 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.
Sometimes, big-box stores will sell inferior alloys labelled “stainless”, with no mention of the alloy. Those fasteners are undoubtedly not the 316SS that is needed in a marine fastener application. Fair Wind Fasteners only deals in fasteners that we would use ourselves. 316 Stainless Fasteners