A2 V2A stainless steel: The hex nut is made of A2 V2A stainless steel and nylon, burr-free and hardened. The lock nuts are resistant to corrosion and rust and can therefore be used outdoors or in humid environments. Anti-vibration: Unlike common nuts, the a2 v2a stainless steel nuts with nylon inserts are designed to prevent the screw or bolt from shrinking or loosening due to vibration. Ease of use: The self-locking nuts have a metric female thread and a low profile that makes them compatible with standard screws or bolts. The nut can be easily tightened with an open-end wrench, socket wrench or torque wrench. Wide range of use: Lock nuts can be used in a variety of industries such as electrical, automotive, mechanical, aerospace, etc. to improve the safety and reliability of fasteners. Internal thread sizes: M4.