Package details: M3x8mm 40pcs M3x12mm 40pcs M3x16mm 40pcs M3x20mm 40pcs M4x8mm 30pcs M4x12mm 30pcs M4x16mm 30pcs M4x20mm 30pcs M5x10mm 20pcs M5x12mm 20pcs M5x16mm 10pcs M5x20mm 10pcs M3 hex nuts 100pcs M4 hex nuts 80pcs M5 hex nuts 50pcs [About Countersunk Screws:] The countersunk screws are mostly used in places where the surface of the parts cannot be raised after installation. The parts to be fastened are thick and thin. The so-called thick, that is, the thickness of the parts to be fastened is larger than the head of the countersunk head screw. Thickness, after the screw is tightened, a part of the screw thread does not enter the threaded hole.