M3-0.5 X 55mm ISO 14581, Metric, Machine Screws, Flat 6-Lobe Drive, Full Thread, A4 Stainless Steel

Machine screws are designed for applications with a pre-tapped hole or mated to a threaded nut.A 6-lobe recess is also known as a hexalobular internal drive.A4 stainless steel is functionally equivalent to 316 grade and is also known as "marine grade"...