Countersunk Phillips Self Tapper Screws create (taps) it's own thread as the screw is being driven in. The head is flat with a smooth tapered underside designed to sit flush in fittings with tapered recesses. Suitable for: Can you be used in stainless light gauge steel aluminium certain plastics and timber. To ensure the best result it is recommended to always drill a pilot hole Material / Coating: Marine Grade Stainless Steel A4-70 G316 is the ultimate corrosion resistance fastener. Designed to be used in all conditions. The best fastener for marine coastal chemical and food environments. Stainless steels are largely non-magnetic but it is common for stainless steel fasteners to show a small degree of magnetism which is a result of work-hardening during the manufacturing process Can Stainless corrode?: Stainless steel is corrosion-resistant but not corrosion-proof and corrosion can occur if the material is installed or handled incorrectly. The use of tools and drills made from conventional steel during the installation of stainless steel fasteners may also lead to problems. Even the hardest of tools can produce debris that leaves minute steel particles on the stainless steel fastener surfaces or in pre-drilled holes. It is these particles that often rust when exposed to moisture or oxygen and can result in a stained or tarnished finish to the stainless steel material Fastener length: is generally measured from the point where the surface of the material will be when the fastener is installed to the end of the fastener. All material is advisory only and its use by anyone is entirely voluntary. Reliance on it for any purpose by anyone is at the sole risk of that person and Bolt and Nut Australia is not responsible for any loss claim or damages arising therefrom.