The Astro Tools RS6M 50pc M6 6mm Steel Rivet Studs are zinc-plated steel rivets with an M6x1.0 thread pitch. They have an outside diameter of 8.9mm and require a 9mm (3/8") drill hole. With a length of 13.7mm and an overall length of 27.5mm, these rivets are designed for heavier-duty fastening applications.