From the Manufacturer Simpson Swan Secure T18N200FNB 316 Stainless Steel 18-Gauge Brad Nails contain more Nickel than a comparable 304SS fastener. This increases the corrosion protection in the harshest environments. Simpson Swan Secure 316 stainless steel nails are manufactured with very high steel tensile strengths ranging from 125,000 to 145,000 pounds per square inch making them leaders in the industry. Convenient 500 count packs are an economical way to purchase 316 stainless steel fasteners.