1720813 is a Bossard product number for self-tapping hexagonal screws with a thread diameter of M6, coarse thread, a shank diameter of 6 mm, and a length of 13 mm. They are made of steel, zinc-plated and Class 8 stamped, have a cylindrical head with a metric Coarse thread pitch, and a slightly rounded top. They are suitable for plastics, light alloys, and sheet metal.