This is a 4-piece metric M10x1.5 stud & nut set, consisting of 2 studs and 2 nuts. The thread pitch of both stud and nut is M10x1.5. The nuts feature a self-locking design, so when they are fastened to a stud by hand, they will stop when they reach the "locking" portion. You will then need a wrench or socket to fasten it further, at which point it will "lock" in place. The nut is about 10 mm in height, and the flange diameter is 17.6mm.Stud is about 42mm long. Made of High Strength steel with copper plating Self-locking nuts are especially useful for exhaust systems, where vibrations could cause regular, non-locking nuts to gradually loosen and come off. Premium quality, high strength (grade 8) and temperature resistant for exhaust system applications, including the exhaust manifold and exhaust flange pipe. Package Includes: stud & nut 2 set Note: *No installation Tool & No instruction is Included, Professional Installation is Recommended* Due to light and screen difference, the item's color may be slightly different from the pictures. Please allow 1-5mm deviation due to manual measurement. THANK YOU for SHOPPING WITH US! Have a nice day