Usage Tips:These threaded insert nuts are widely used in 3D Printing, molding, for fastening, can be installed in the cone hole by ultrasonic or heat,or in the process. Since the insert has a conduction valve, there is no need to back-drill and counter-sink the hole.Type:Metal Lock NutsSpecification:A:220PCSM2x3x3.5=25PcsM2x4x3.5=25Pcs M2.5x3x3.5=25PcsM2.5x4x3.5=25Pcs M3x3x4=25PcsM3x4x4=25Pcs M3x5x4=25Pcs M4x4x6=25PcsM5x5x7=10PcsM6x6x8=10PcsColor: GoldMaterial: IronPackage Contents:1Set x Heat Insert NutOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.