JM Hardware® Metal lock nut is a type of nut that has a special locking feature. It has two threads with one being a left-handed thread and the other being a right-handed thread. When tightened, the left-handed thread will cause the nut to jam against the mating material, creating a secure, vibration-resistant connection. It is commonly used in applications such as automotive, industrial, and aerospace, where a secure and reliable connection is required.