[M12]

[M24]

As the definitive version of loosening nuts, the "Hard Lock Nut" is widely supported in the industry, from steel structures such as railways and bridge beams, to cars, motorcycles, and industrial machinery.
When installing a hard lock nut, first attach the convex nut to the bolts that pass through the fastener. Tightening method is the same as a regular hex nut, and use a common tool to tighten it. After that, the concave nut is inserted by hand through the bolt, leaving about one thread of the convex bolt, and tighten it with the specified torque.