The head can be punched below the surface for a concealed finish. Manufactured from A2 Stainless Steel offering superior corrosion resistance, perfect for external applications. Stainless steel must be used where there is corrosive environment and/or the base material has inherent corrosive characteristics e.g. Green Oak. A2 stainless steel for external applications" Shank Dia. mm: 2.65 Length mm: 40 Material: Austenitic Stainless Steel (A2-304) Approx. Pcs Per 1kg: 550Size 40 x 2.65 - 10 Kilograms Timco Round Lost Head Nails - Stainless Steel in Silver