tamper-proof

5/8-11 x 14 A307 Grade A Carriage Bolt HDG

1-8 x 1 1/2 Grade 8 Hex Cap Screw Yellow Zinc Plated

They are nickel plated for appearance

1 1/8-7 x 4 Socket Cap Screw Alloy

5/8-18 x 6 Hex Cap Screw SS 18-8 (A2) 1 3/4-5 Socket Cap Screws Alloy tamper-proof5 8 18 x 6 Hex Cap Screw SS 18 8 (A2) . 18 8 stainless steel hex cap screws will have a typical composition of 18% chromium and 8% nickel. These percentages exist in 303, 304 and 305 series stainless steels so 18 8 is used at times to designate any and all of those alloy groups. 18 8 stainless steel offers good corrosion resistance and machines easily but will over time stain in coastal environments. They are also acceptable for use in ACQ pressure