From the Manufacturer
Kreg Blue-Kote is the next generation of rust-resistant screw and the best choice in the majority of Pocket-Screw applications. Through an extensive process which chemically combines three special anti-corrosion layers, Blue-Kote screws take on amazing new rust-resistant properties which are consistently rated 400% higher than our old zinc-plated screws.
Three chemically-combined anti-corrosion layers give Kreg’s Blue-Kote screws up to 400% more weather resistance than zinc-plated screws. They’re an ideal choice for garden and patio furniture, as well as for general exterior construction. Self-tapping screw tips make for easy driving. Case hardened steel won’t bend or break, and the deep-seated #2 square drive heads eliminate “cam out,” ensuring a tight, solid joint.