Stainless Steel phillips flat head screws are countersunk. This style helps the screw sit flush with the surface. Marine Bolt Supply offers both standard type 18-8 and type 316 stainless steel options. Type 18-8 stainless steel has a high resistance to rust and corrosion and may be mildly magnetic. Type 316 stainless offers superior resistance to rust and corrosion and is recommended for chemical, salt water or coastal environments. Please select the category type below.