Hexagon socket nut screw rivet locking screw Material: 304 chrome steel Internal diameter: M3 M4 M5 M6 M8 M10 Outside diameter of cylinder: 4/5/6/8/10/13mm Length: 5~100mm Size: Thread internal diameter (M/d) x Cylinder Length (L) x Cylinder Outer diameter (d1) (Head thickness (k)/ screw outer diameter (dk) will range by way of 0.1~0.2mm thanks to size) For bulk purchase, you possibly can contact the vendor to get the final quotation.