These Hexagon Head set screws are ISO Metric Threaded with an M4 thread size. Each screw is manufactured from Class 8.8 medium tensile strength carbon steel, quenched and tempered with an as produced oiled black finish. Each product has a minimum proof load of 580 MPA and can be purchased in different lengths. Features and Benefits As produced slightly oiled finish Sold in boxes of 500 to ensure you have plenty of screws for multiple applications Available in a variety of lengths to suit your needs, all with an M4 thread size Manufactured from Class 8.8 steel for optimum resilience Typical Applications Engineering Construction DIY Standards DIN 933 EN 24017 ISO 4017