L9® High Tensile Strength Hex Collared Locknuts are designed for use in high stress, severe service environments. The highest mechanical strength off-the-shelf fastening system available, its special features control torque-tension characteristics to develop high clamp loads when using properly controlled tightening methods. Brighton Best manufactures L9® nuts from AISI alloy steels. Collared prevailing torque metal locknuts are used in applications where assemblies are subject to vibration.