Stover lock nuts are one piece, all-metal prevailing torque hex nuts with a conical top and a flat bottom bearing surface with chamfered corners. The locking action, created by distortion of their top threads, is said to be capable of withstanding severe vibration and shock loads. Since they are top locking and only the bottom surface is flat, Stover lock nuts are considered one way lock nuts because they are installed one way—top up. Being all-metal, they are not subject to the temperature and chemical limitations of non-metallic (such as nylon) insert type lock nuts. Used in the automotive, agricultural equipment and metalworking industries, their cone shape allows for proper orientation during automated assembly making them popular for high volume applications. Stover lock nuts are also called: automation lock nuts, Autolock nuts, Crownlock nuts, Unitorque nuts. Lock washers are not used with prevailing torque lock nuts.