This cap's durability is rugged enough to tackle any application within 25 miles of a saltwater coast. Its high-quality construction includes a 24-gauge stainless steel hood with scalloped corners and straight cut edges, an 18-gauge 3/4" expanded stainless steel mesh, and a 16-gauge stainless steel base integrated for added strength. The outside mounting design engineers a maximum free air space allowing uninhibited chimney draft.